A shock absorber , comprising: a shock absorber main body that absorbs a shock input to a vehicle ; a gas spring chamber which is provided inside the shock absorber main body , and inside which gas is sealed, and which absorbs the shock by a gas spring that is based on the gas; an auxiliary gas spring chamber , inside which the gas is sealed, and which communicates with the gas spring chamber , and which is formed in a cylindrical shape; a movable partition wall which is provided slidably in an axial direction inside the auxiliary gas spring chamber ; a gas spring chamber side gas chamber which is sectioned by the movable partition wall in the auxiliary gas spring chamber and which communicates with the gas spring chamber ; and an elastic body side gas chamber which is sectioned by the movable partition wall in the auxiliary gas spring chamber , and which is formed on an opposite side of the movable partition wall to the gas spring chamber side gas chamber , and which has an elastic body having a prescribed modulus of elasticity that urges the movable partition wall towards the gas spring chamber side gas chamber , wherein the movable partition wall moves towards the elastic body side gas chamber so as to increase a volume of the gas spring chamber side gas chamber , as pressure inside the gas spring chamber increases, wherein the elastic body of the elastic body side gas chamber has a gas spring that is based on the gas sealed therein, characterized in that the elastic body of the elastic body side gas chamber further has a metal spring , wherein an auxiliary tube is arranged in the elastic body side gas chamber and defines an initial load of the metal spring . a shock absorber main body that absorbs a shock input to a vehicle ; a gas spring chamber which is provided inside the shock absorber main body , and inside which gas is sealed, and which absorbs the shock by a gas spring that is based on the gas; an auxiliary gas spring chamber , inside which the gas is sealed, and which communicates with the gas spring chamber , and which is formed in a cylindrical shape; a movable partition wall which is provided slidably in an axial direction inside the auxiliary gas spring chamber ; a gas spring chamber side gas chamber which is sectioned by the movable partition wall in the auxiliary gas spring chamber and which communicates with the gas spring chamber ; and an elastic body side gas chamber which is sectioned by the movable partition wall in the auxiliary gas spring chamber , and which is formed on an opposite side of the movable partition wall to the gas spring chamber side gas chamber , and which has an elastic body having a prescribed modulus of elasticity that urges the movable partition wall towards the gas spring chamber side gas chamber , wherein the movable partition wall moves towards the elastic body side gas chamber so as to increase a volume of the gas spring chamber side gas chamber , as pressure inside the gas spring chamber increases, wherein the elastic body of the elastic body side gas chamber has a gas spring that is based on the gas sealed therein, characterized in that the elastic body of the elastic body side gas chamber further has a metal spring , wherein an auxiliary tube is arranged in the elastic body side gas chamber and defines an initial load of the metal spring . <EOS>