To provide a shock absorber with a vehicle height adjusting function capable of preventing the generation of transference of gas from a high-pressure gas chamber to a low-pressure gas chamber even if pumping is repeatedly performed to adjust vehicle height and, consequently, maintaining the excellent vehicle height adjusting function with pumping for a long time, and capable of improving comfortableness to ride.

This shock absorber 10 with a vehicle height adjusting function is structured by including a cylinder 12, a piston 28, a piston rod 14, a high-pressure liquid chamber 18, a low-pressure reservoir chamber 44, the high-pressure gas chamber 16, a diaphragm film 20, the low-pressure gas chamber 46, and a pump mechanism 54. Operating fluid is sucked from inside the reservoir chamber 44 to the high-pressure liquid chamber to adjust vehicle height by pumping work of the pump mechanism 54. The reservoir chamber 44 and the low-pressure gas chamber 46 are partitioned by a diaphragm film 48.