PROBLEM TO BE SOLVED: To further rationally constitute a mechanism by the minimum number of components, when a back bottom is erected, the mechanism slidably moving the back bottom to a head side of a bed.SOLUTION: An operation mechanism of the back bottom of an electric bed includes: a rail part 3 that is provided on a frame 2 and extends in the length direction of the bed a guide object part 1a that is provided on a back bottom 1 at the end of a foot side F of the bed and is guided by the rail part 3 a lift arm body 5 that is erected on the frame 2 in a head side H of the bed with respect to the rail part 3 and extends from a drive shaft 4 a linkage arm body 12 extending from the drive shaft 4 and a link body 13 for linking the link arm body 12 to the back bottom 1. When the drive shaft 4 is normally rotated, the back bottom 1 is erected with the guide object part 1a used as a center by the lift arm body 5 for upward moving a slide contact part 5a, and when and after the back bottom 1 reaches a prescribed erection position, the guide object part 1a of the back bottom 1 is moved to the head side H of the bed by the linkage arm body 12.
