{
  "spec_version": "3",
  "endpoint": "timeline",
  "stock_code": "5233",
  "company_name": "太平洋セメント",
  "content_lang": "ja",
  "meta_lang": "en",
  "canonical_url": "https://the-shashi.com/tse/5233/",
  "api_url": "/api/5233/timeline.json",
  "updated": "2026-09-05",
  "license": "© 2026 Yutaka Sugiura. All rights reserved.",
  "attribution": "The社史 (the-shashi.com) — https://the-shashi.com/tse/5233/",
  "source": {
    "primary": [
      "有価証券報告書",
      "日経ビジネス",
      "週刊東洋経済",
      "IR"
    ],
    "extraction": "有価証券報告書の沿革を基礎に、社史・報道で補完",
    "row_field": "source"
  },
  "timeline": [
    {
      "date": "1881/5",
      "importance": 2,
      "event": "小野田セメント設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1883/4",
      "importance": 1,
      "event": "官営深川工作分局を借り受け（浅野セメント/日本セメントの源流）",
      "source": null
    },
    {
      "date": "1903/12",
      "importance": 2,
      "event": "日本初の回転窯によるセメント製造を開始",
      "source": null
    },
    {
      "date": "1912/10",
      "importance": 1,
      "event": "浅野セメント設立",
      "source": null
    },
    {
      "date": "1923/1",
      "importance": 1,
      "event": "秩父セメント設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1929/5",
      "importance": 1,
      "event": "西多摩工場新設、早強セメント製造開始",
      "source": null
    },
    {
      "date": "1934/1",
      "importance": 1,
      "event": "日本初の低熱セメントの製造を開始",
      "source": null
    },
    {
      "date": "1939/10",
      "importance": 2,
      "event": "旧日本セメントを合併",
      "source": null
    },
    {
      "date": "1947/5",
      "importance": 1,
      "event": "日本セメントに商号変更",
      "source": null
    },
    {
      "date": "1949/5",
      "importance": 1,
      "event": "株式上場",
      "source": "有価証券報告書"
    },
    {
      "date": "1955/4",
      "importance": 1,
      "event": "埼玉工場が竣工",
      "source": "有価証券報告書"
    },
    {
      "date": "1962/7",
      "importance": 1,
      "event": "熊谷工場が竣工",
      "source": "有価証券報告書"
    },
    {
      "date": "1972/2",
      "importance": 1,
      "event": "明星セメントの全株式取得",
      "source": "有価証券報告書"
    },
    {
      "date": "1983/3",
      "importance": 1,
      "event": "創立100周年、中央研究所新築",
      "source": null
    },
    {
      "date": "1984/8",
      "importance": 1,
      "event": "大日本セメント共同事業株を設立",
      "source": null
    },
    {
      "date": "1990/10",
      "importance": 2,
      "event": "カリフォルニア・ポルトランド・セメントを買収",
      "source": "有価証券報告書"
    },
    {
      "date": "1994/10",
      "importance": 2,
      "event": "小野田セメントと秩父セメントが合併し秩父小野田発足",
      "source": "有価証券報告書"
    },
    {
      "date": "1995/4",
      "importance": 1,
      "event": "ギソンセメントコーポレーションを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1998/10",
      "importance": 3,
      "event": "秩父小野田と日本セメントが合併し太平洋セメント発足",
      "source": "有価証券報告書",
      "link": "/tse/5233/decisions/taiheiyo-cement-merger-1998/"
    },
    {
      "date": "2000/4",
      "importance": 3,
      "event": "ゼロエミッション事業部を設置し廃棄物処理事業を本格化",
      "source": "日経ビジネス",
      "link": "/tse/5233/decisions/waste-recycling-2000/"
    },
    {
      "date": "2003/5",
      "importance": 1,
      "event": "本社を移転",
      "source": "有価証券報告書"
    },
    {
      "date": "2007/4",
      "importance": 1,
      "event": "パシフィックシステムがジャスダック上場",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/3",
      "importance": 2,
      "event": "初の純損失を計上",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/5",
      "importance": 1,
      "event": "本社を移転",
      "source": "有価証券報告書"
    },
    {
      "date": "2010/3",
      "importance": 1,
      "event": "2期連続の純損失",
      "source": "有価証券報告書"
    },
    {
      "date": "2012/4",
      "importance": 1,
      "event": "福田修二が代表取締役社長就任",
      "source": "有価証券報告書"
    },
    {
      "date": "2015/6",
      "importance": 3,
      "event": "カリフォルニア州のオログランデ工場を買収",
      "source": "有価証券報告書",
      "link": "/tse/5233/decisions/us-west-coast-2015/"
    },
    {
      "date": "2016/8",
      "importance": 1,
      "event": "デイ・シイを株式交換により完全子会社化",
      "source": "有価証券報告書"
    },
    {
      "date": "2018/4",
      "importance": 1,
      "event": "不死原正文が代表取締役社長就任",
      "source": "有価証券報告書"
    },
    {
      "date": "2022/6",
      "importance": 3,
      "event": "石炭サーチャージ制度の導入を表明（8月に撤回し1トン3000円値上げへ）",
      "source": "週刊東洋経済",
      "link": "/tse/5233/decisions/price-pass-through-2022/"
    },
    {
      "date": "2023/3",
      "importance": 2,
      "event": "純損失▲332億円",
      "source": "有価証券報告書"
    },
    {
      "date": "2024/4",
      "importance": 1,
      "event": "田浦良文が代表取締役社長就任",
      "source": "有価証券報告書"
    },
    {
      "date": "2025/3",
      "importance": 1,
      "event": "営業利益778億円、過去高水準",
      "source": "IR"
    }
  ]
}