To provide a coffin capable of reducing it in size and weight and reducing the increase and complication of an assembly process by simplifying the configuration of a coffin body.

A coffin 100 is configured to include a coffin body 101 and a lid 140. The coffin body 101 is configured to include a cardboard trunk 110 and wood trunk reinforcing bodies 120. The trunk 110 is configured to include a bottom 111 on which a dead body D is placed and lateral walls 112 arranged in a standing manner in the width direction of the bottom 111. The trunk reinforcing body 120 is configured to have bottom reinforcing parts 121 arranged at lower surfaces of both the side parts in the longitudinal direction of the bottom 111 of the trunk 110, lateral wall reinforcing parts 122 arranged in a standing manner at both the side parts in the width direction of the bottom reinforcing part 121, and reinforcing part 124 in a width direction arranged between the two lateral wall reinforcing parts 122. The trunk reinforcing body 120 is attached to and detached from the trunk 110 through a connecting member 130. A lid 140 is configured to have a lid body 141 and a positioning body 142.