Abstract: A pressure-receiving chamber in an actuator and an air chamber of an air spring for displacing a shutter in a piston rod communicate with other through an air passage provided in the piston rod. The air passage includes a small-diameter hole of a rod insertion hole in the piston rod and an air hole formed in a side wall of the piston rod. By this arrangement, an external pipe such as used in a conventional air suspension apparatus for enabling communication between the actuator and the air spring becomes unnecessary, and the pressure in the air chamber is introduced into the pressure-receiving chamber in the actuator through the air passage in the piston rod. Therefore, a problem such as leakage of air can be avoided, leading to a reduction in the number of necessary parts.