Disc brake and piston boot

A disc brake, comprising:

• a piston configured to press at least one of a pair of pads opposed to each other on both surfaces of a disc;
• a cylinder which includes:
• a bottomed bore portion for accommodating the piston movably in an axial direction;
• and a step portion formed on an opening end side of the bottomed bore portion from which a tip of the piston protrudes, the step portion having an annular shape and a diametrical dimension larger than an inner diameter of the bottomed bore portion;
• and
• a piston boot which is arranged between the tip side of the piston and the step portion of the cylinder, and includes a bellows portion configured to expand and contract along with the movements of the piston,
• wherein the piston boot includes:
• a large diameter fitting portion having an annular shape and containing an annular metal member so as to be fitted to the step portion;
• the bellows portion, which extends from the large diameter fitting portion, is increased radially outside beyond the large diameter fitting portion to an outer peripheral side, and is also deformed and extended from the large diameter fitting portion toward an inner peripheral side;
• and
• a small diameter fitting portion which is formed, at an end portion of the bellows portion, into an annular shape having a shorter diameter than that of the large diameter fitting portion so as to be fitted to an outer periphery of the piston, and
• wherein the large diameter fitting portion of the piston boot includes a cut-away portion at a position on the bellows portion side so that a part of the metal member is exposed to an outside.