Abstract: A power seat apparatus in a vehicle body includes a first shaft through which the rotational torque is transmitted to a first mechaism for moving a front portion of a seat-cushion vertically, a second shaft through which the rotational torque is transmitted to a second mechanism for moving a rear portion of the seat-cushion vertically and a third shaft through which the rotational torque is transmitted to a third mechanism for moving the seat-cushion in the lengthwise direction. The power seat apparatus further includes a mechanical control device engaging a third clutch to the third shaft during the disengagement of a first clutch from the first shaft and a second clutch from the second shaft and disengaging the third clutch from the third shaft during either the engagement of the first clutch to the first shaft or the engagement of the second clutch to the second shaft. With this arrangement no solenoid needs to be used in the control device, and consequently noise emission is not generated.