Abstract: A bed device comprises a bottom unit including a back bottom, a hip bottom, and a leg bottom connected to one another, and a drive mechanism capable of changing a posture of the bottom unit from a supine posture in which the back bottom, the hip bottom, and the leg bottom are aligned horizontally to a back lifting posture and a sitting posture. The drive mechanism allows the back bottom to stand up about the hip bottom in the change from the supine posture to the back lifting posture, and rotates the leg bottom around one end of the hip bottom and accommodates the leg bottom on a back side of the hip bottom in the change from the back lifting posture to the sitting posture.

Abstract: A bed frame is provided with a base plate. The base plate has a fixed base plate portion secured to the bed frame, a hip plate portion and a back plate portion sequentially and rotatively connected to an end of said fixed base plate portion and a first leg plate portion and a second leg plate portion sequentially and rotatively connected to another end. The back plate portion is arranged to be raised by a back elevating mechanism. When the back plate portion has been raised, the hip plate portion is moved in synchronization with the rotation in the raising direction. At this time, since the back plate portion is raised to make an angle larger than that of the hip plate portion, the hip of a user is not held between the fixed base plate portion and the back plate portion.