PURPOSE: To improve the degree of freedom in the arrangement of electrical equipment and cooling performance by extending an auxiliary foot placing board behind a foot placing board along the lower parts of both the side surface of a rear cover covering the lower part of a driver's seat, forming a recessed part having an air vent hole which is long in the longitudinal direction and a bulging-out part for accommodating the electrical equipment on the side surface of the rear cover set along the uppeer surface of the auxiliary foot placing board, and taking-in the outside air into the bulging-out part.

CONSTITUTION: The left and right auxiliary foot placing boards 96 extending aslantly rearward in continuation to the rear part of the foot placing board are formed on the left and right side surfaces of a rear cover. A recessed part 114 which is long in the longitudinal direction is formed so as to be set along the upper surface of the auxiliary foot placing board 96, and a bulging-out part 116 which bulges outside a car body is formed over the recessed part 114. Further, a proper number of air vent holes 118 which are long in the longitudinal direction are formed on the recessed part 114. The electric equipment such as ignition coil 120, etc., is accommodated inside the bulging-out part 116, and the stream of the outside air generated along the upper surface of the auxiliary foot placing board 96 and the recessed part 114 is introduced into the bulging-out part 116 from the air vent hole 118, and cooled.