A suspension device comprising: a cylinder that has an axial center extending in one direction and has first and second ends (1a, 1b); a first piston provided movably in an axial direction inside of the cylinder; an inner pipe provided inside of the cylinder to extend in the axial direction between the first piston and the first end (la); a first rod that is coupled to the first piston and extends in the axial direction to be inserted into the inner pipe; a second rod that is coupled to the first piston and extends in the axial direction to project outwardly from the cylinder through the second end (lb); a closure configured to close the first end; a first supporter configured to support the second rod that is movable in the axial direction while closing the second end (lb); a second piston that is provided movably in the axial direction while sealing a space between an outer surface of the inner pipe and an inner surface of the cylinder, wherein a first liquid chamber is formed between the first piston and the first supporter, and inside of the cylinder; a second liquid chamber is formed between the first piston and the second piston, inside of the cylinder and outside of the inner pipe, a liquid passage (2A, 2B) is provided in the first piston, the liquid passage (2A, 2B) connecting the first liquid chamber and the second liquid chamber, wherein a liquid is sealed in the first and second liquid chambers (L1, L2), a first gas chamber is formed between the second piston and the closure, inside of the cylinder and outside of the inner pipe, a second gas chamber is formed inside of the inner pipe, wherein a gas is sealed in the second gas chamber, characterized in that the first rod has a first inner passage that communicates with the second gas chamber, the second rod has a second inner passage that communicates with the first inner passage, the closure has a concave portion directed inwardly of the cylinder, the suspension device further comprises a fitting portion that is fitted to the concave portion while closing an end of the inner pipe, and a gas passage (11b, 121) is formed in at least one of the closure and the fitting portion, the gas passage (11b, 121) communicating with the first gas chamber. a cylinder that has an axial center extending in one direction and has first and second ends (1a, 1b); a first piston provided movably in an axial direction inside of the cylinder; an inner pipe provided inside of the cylinder to extend in the axial direction between the first piston and the first end (la); a first rod that is coupled to the first piston and extends in the axial direction to be inserted into the inner pipe; a second rod that is coupled to the first piston and extends in the axial direction to project outwardly from the cylinder through the second end (lb); a closure configured to close the first end; a first supporter configured to support the second rod that is movable in the axial direction while closing the second end (lb); a second piston that is provided movably in the axial direction while sealing a space between an outer surface of the inner pipe and an inner surface of the cylinder, wherein a first liquid chamber is formed between the first piston and the first supporter, and inside of the cylinder; a second liquid chamber is formed between the first piston and the second piston, inside of the cylinder and outside of the inner pipe, a liquid passage (2A, 2B) is provided in the first piston, the liquid passage (2A, 2B) connecting the first liquid chamber and the second liquid chamber, wherein a liquid is sealed in the first and second liquid chambers (L1, L2), a first gas chamber is formed between the second piston and the closure, inside of the cylinder and outside of the inner pipe, a second gas chamber is formed inside of the inner pipe, wherein a gas is sealed in the second gas chamber, characterized in that the first rod has a first inner passage that communicates with the second gas chamber, the second rod has a second inner passage that communicates with the first inner passage, the closure has a concave portion directed inwardly of the cylinder, the suspension device further comprises a fitting portion that is fitted to the concave portion while closing an end of the inner pipe, and a gas passage (11b, 121) is formed in at least one of the closure and the fitting portion, the gas passage (11b, 121) communicating with the first gas chamber.