To obtain an ideal structure as a Japanese-style room specification by providing a Tatami mat (rush mat) as a bed in response to a request that a user wants to sleep in bedding laid on a tatami mat, and also arranging an elevating/lowering mechanism for usage as care.

The Tatami mat 1 is lifted up by connecting the body part 1a of the Tatami mat 1 without its edging part 1b to a base 3 being a little smaller than the body part 1a, through the use of X shape parallel links 4a. The thickness of the X shape parallel links 4a in a folded state is not more than that of the Tatami mat. The edging part 1b separated from the body part 1a is placed on and supported by a plurality of lock parts 2 which are arranged and projected in the outer periphery of the body part 1a. Bellows 5 are attached between the bases 3 and the body part 1a, so that legs are prevented from entering at least the inner part of the bases. A tatami bed in the folded state has a thickness being the same as that of the normal Tatami mat.