A controller assembly includes a plurality of controller units, and a heat dissipating unit interposed between the controller units. Male and female connectors are disposed in the controller units, and the connectors thereof are fitted to female and male connectors of the heat dissipating unit to thereby establish electrical contact therebetween. Upon driving electric actuators, heat generated in circuit boards of the controller units is dissipated to the exterior through a plurality of heat dissipating protrusions provided on the heat dissipating unit, so that heat generating sources of the circuit boards are cooled.