A shock absorber, comprising: a shock absorber main body composed of a vehicle-body side tube and a wheel side tube to be slidably inserted into the vehicle-body side tube via a pair of upper and lower bearings (30, 31), the upper bearing being mounted on the outer periphery of the wheel side tube, the lower bearing being mounted on the inner periphery of the vehicle-body side tube and a lubrication clearance being formed between the pair of upper and lower bearings (30, 31); a damper including a cylinder which stands in an axial center part of the wheel side tube and stores a working fluid, a piston which is held in sliding contact with the inner periphery of the cylinder and partitions the interior of the cylinder into two working chambers (A, B), and a rod which intrudes into and exits from the cylinder via the piston; a reservoir chamber formed between the shock absorber main body and the damper, composed of an air chamber and a working fluid chamber and configured to compensate for the working fluid that becomes excessive and insufficient in the damper; a partition wall member partitioning the working fluid chamber into an upper working fluid chamber and a lower working fluid chamber; a flow path formed in the partition wall member and having a check valve to permit only a movement of the working fluid from the upper working fluid chamber to the lower working fluid chamber; and a communication path allowing communication between the lower working fluid chamber and the lubrication clearance; wherein a cross-sectional area of the lubrication clearance and that of the rod are different. a shock absorber main body composed of a vehicle-body side tube and a wheel side tube to be slidably inserted into the vehicle-body side tube via a pair of upper and lower bearings (30, 31), the upper bearing being mounted on the outer periphery of the wheel side tube, the lower bearing being mounted on the inner periphery of the vehicle-body side tube and a lubrication clearance being formed between the pair of upper and lower bearings (30, 31); a damper including a cylinder which stands in an axial center part of the wheel side tube and stores a working fluid, a piston which is held in sliding contact with the inner periphery of the cylinder and partitions the interior of the cylinder into two working chambers (A, B), and a rod which intrudes into and exits from the cylinder via the piston; a reservoir chamber formed between the shock absorber main body and the damper, composed of an air chamber and a working fluid chamber and configured to compensate for the working fluid that becomes excessive and insufficient in the damper; a partition wall member partitioning the working fluid chamber into an upper working fluid chamber and a lower working fluid chamber; a flow path formed in the partition wall member and having a check valve to permit only a movement of the working fluid from the upper working fluid chamber to the lower working fluid chamber; and a communication path allowing communication between the lower working fluid chamber and the lubrication clearance; wherein a cross-sectional area of the lubrication clearance and that of the rod are different.