To improve finish of the external appearance of a coffin by eliminating steps between tiltable left/right side plates and end plates, and to make manufacturing of the side plates and end plates possible by a simple machining operation.SOLUTION: The folding corrugated cardboard coffin is made by folding a reinforced corrugated cardboard material in a box shape along V grooves, including: a rectangular bottom box 21； tiltable side plates 22； a folding margin plate 23 that is connected through the V groove in front and in the rear of the side plates 22； and downward U-shaped end plates 24 that are folded in from above the folding margin plate 23 and that hold the erected state of the side plates 22. The side plates 22 are, in the upper end part 22b of the side plates and in front and in the rear end of the coffin of the side plate fold back part 22c, provided with a side plate connection face Fs which is formed along the V groove for folding the side plates 22 and the folding margin plate 23. The end plates 24 are, in the end plate upper end part 24b and the lateral ends of the coffin of the end plate fold back part 24c, the inclined face mutually approaching from a position coincident with the lateral width of the coffin in view from the plane direction toward the inside of the coffin, and are provided with an end plate connection face Ft that is superimposed on the side plate connection face Fs.SELECTED DRAWING: Figure 4【課題】可倒式の左右側板と妻板との繋ぎ目に段差をなくして棺の外観の仕上がりを良好にし、簡単な加工作業により側板と妻板を製造可能にする。【解決手段】折畳式段ボール棺は、強化段ボール材をＶ溝に沿って箱状に折り曲げるもので、矩形の底箱２１と、可倒式の側板２２と、その前後にＶ溝を介して連結される折り代板２３と、折り代板２３の上方から落とし込まれて側板２２の起立状態を保持する下向きコ字状の妻板２４とを備える。側板２２は、側板本体部２２ａ、側板上端部２２ｂおよび側板折返し部２２ｃの棺前後端に、側板２２と折り代板２３とを折り曲げるためのＶ溝に沿って形成される側板繋ぎ面Ｆｓを有する。妻板２４は、妻板上端部２４ｂおよび妻板折返し部２４ｃの棺左右端に、平面方向から見て棺左右幅と一致する位置から棺内側に向けて互いに近づくように傾斜する面であって、側板繋ぎ面Ｆｓに重なる妻板繋ぎ面Ｆｔを有する。【選択図】図４
