To improve the practicability of a vehicular air spring device with a shock absorber separated therefrom.

The air spring device includes: (a) a rod 80 installed on either of a vehicle body side casing 60 or a wheel side casing 62; and (b) a rod retaining cylinder 82 which is installed on the other one and slidably retains the rod 80 as well as a substantially rod-like expansion guide 66 for regulating the direction of expansion movement of the air spring device 10 provided in a pressure chamber 90. The vehicle body side casing 60 has a body part 70 and a protruding part 72, an upper edge of the expansion guide 66 is disposed inside the protruding part 72, and the air spring device 10 is connected to a side member 110 in the body 70 of the vehicle body side casing 60. Regardless of the provision of the expansion guide 66, the protruding part 72 storing part thereof is protruded above a connection part to the side member 110, thus relatively reducing a vertical space necessary for installation.