In a bed combination method of forming a bed (11) on which a person lies by combining a wheelchair (13) with a recess part (23a) of a bed base portion (23) of a bed main portion (12), a posture of a seat portion (31) of the wheelchair is changed from a chair posture to a tilt posture where the seat portion is inclined in such a manner that a position of a footrest is higher than the base portion by a tilt action while a shape of the seat portion is maintained as a chair shape, and then, the wheelchair is moved to the recess part of the base portion, and the seat portion is changed from the tilt posture to a non-tilt posture.
