A vehicle reinforcing member includes first and second pistons movable in an axial direction in a cylinder. An inside of the cylinder is sectioned into a gas chamber and a main liquid chamber by the first piston, and the main liquid chamber is sectioned into a first sub-liquid chamber and a second sub-liquid chamber by the second piston. Gas is sealed in the gas chamber, and liquid is sealed in the first and second sub-liquid chambers. A piston rod is coupled to the second piston. The cylinder and the piston rod are respectively coupled to two locations of a vehicle body. A communication path connects the first sub-liquid chamber to the second sub-liquid chamber. A moving amount of the liquid in the communication path is adjusted by an adjuster such that a moving load through the second piston is adjusted.