To provide a coffin of aesthetic appearance and provide high-grade sensation similar to the conventional coffin of non-knock-down type.

Side board base plates 2 and 3 are fixed to the both side edges in the long sides of a bottom board 1 respectively, end plate base plates 4 and 4 are fixed to the both side edges in the narrow sides of the bottom board 1 respectively, side board tiltable plates 5 and 6 are tiltably connected onto the insides of the both side board base plates 4 and 4 respectively, and end plates slide-in plates 8 and 8 are constituted to be slid in between the respective side board tiltable plates 5 and 6 on the both end plate base plates 4 and 4. The outside faces of the side board base plates 2 and 3 are formed to be positioned inside the outside faces of the side board tiltable plates 5 and 6, and the side board tiltable plates 5 and 6 are formed with side board base plate outside cover parts 5d and 6d extending downward covering the outside faces of the side board base plates 2 and 3, and side board base plate end cover parts 5e and 6e extending downward covering the both ends of the side board base plates 2 and 3.