PURPOSE: To miniaturize a variable shock absorber by interposing a check valve at a piston between a first fluid chamber part and the other fluid chamber part of a pair of concentric fluid chambers, and providing a solenoid valve for controlling fluid flow, between a pair of concentric fluid chambers.

CONSTITUTION: An ECU 22 actuates a fluid flow solenoid control valve 38 by a signal of a length sensor 26 to lead fluid pressure into a liquid reservoir 98 of a strut 24 and to make it flow into a first fluid chamber part 104 against a spring 142, thus keeping the distance between parts 82, 84 constant according to vehicle load. The liquid reservoir 98 is pressurized by gas pressure in a gas chamber 113 on a diaphragm 112. An internal between the first and a second fluid chamber 104, 106 communicates with the fluid chamber 104 through a check valve 202 of a piston 102, and the fluid chamber 106 communicates with the fluid chamber 104 through a fluid chamber 172, a throttle, a fluid chamber 174 and a passage 212, so that current-carrying in a solenoid 28 is controlled to adjust the cushioning rate of the strut 24 through a pintle valve 224. Excellent variable cushioning can therefore be obtained in spite of being relatively compact.