To secure bodily safety by providing a switch to open when an elevating body is above a position separated from the lowest position and to close when it is below it and controlling a motor between adjacent elevating bodies by this switch.

When a switch 32a for lowering is pressed by closing a switch part for an elevating body in a state where interlock switches 40b, 40c are closed, a switch of an electromagnetic switch is closed by energizing a coil 36a, a motor is reversely rotated and the elevating body is lowered. When it reaches near the ground, in the case when the switch 32a for lowering is finished operating, energization of the coil 36a is eliminated, the switch of the electromagnetic switch is opened, and rotation of the motor is stopped. In the case when an operator leaves his position in this state, an interlock switch 40a is closed, and even when the elevating body is not certainly lowered to the lowest position, a motor driving circuit of an adjacent elevating body is in a state free to move.