Shock absorber

A shock absorber comprising:

• a cylinder in which a working liquid is enclosed;
• a piston which is slidably fitted into the cylinder and divides the inside of the cylinder into two chambers;
• a piston rod which is connected to the piston and extends to the outside of the cylinder;
• a seal member that slidably contacts to the piston rod and prevents the working liquid from leaking to the outside of the cylinder;
• a friction member that is provided on the inner side of the cylinder in relation to the seal member, the friction member including an annular elastic rubber portion which slidably contacts to the piston rod and an annular base portion to which the elastic rubber portion is fixed;
• and
• a communication path which decreases a pressure difference between both sides of the friction member in an axial direction,
• wherein the base portion includes an annular disk portion, and
• wherein the elastic rubber portion includes:
• an inner peripheral connection portion connected to an inner peripheral portion of the annular disc portion;
• a minimum inner diameter portion that is disposed on a position apart from an end portion in a thickness direction of the annular disk portion, the minimum inner diameter portion provided on an inner circumferential side of the annular disc portion;
• an inner peripheral surface having an inner diameter increasing from the minimum inner diameter portion to a direction toward the annular disk portion;
• and
• a protrusion suppression structure portion provided at least partially in a circumferential direction of the inner peripheral surface, the protrusion suppression structure portion configured to suppresses protruding of the inner peripheral surface in a radial direction.