To provide a bed for easily and strongly expanding a bed space correspondingly to the change of the conditions even when the using state of the bed is changed due to the birth of a child, or the like, after a marriage.

This bed is provided with the frame 7 of a bed body 1, a bottom board 9 surrounded by the frame 7, a mattress 8 mounted on the bottom board 9, bisected head frames 6 arranged at the head part of the bed body 1, a headboard 2 housed in the head frames 6 and cushions 3 and 4 assembled in the head frames 6. The head frames 6 are attached to the optional positions of the side faces of the frames 7.