| 摘要 |
PROBLEM TO BE SOLVED: To provide a mattress device which can be smoothly curved when the mattress device is curved for raising an upper body of a user.SOLUTION: A mattress device includes: a plurality of mattress parts 32, 33, 34 used by vertically overlapping them; a convex part which is formed in a longitudinal direction on one of a top surface and an underside of the lower side mattress part and the upper side mattress part that are brought into contact with each other; and a concave part which is formed in the longitudinal direction on the other surface out of the top surface and the underside in such a manner that the convex part engages. |
