Disc brake system

PROBLEM TO BE SOLVED: To provide a disc brake device to automatically regulate the position of a pad to a rotor and reduce the size of a whole shape. SOLUTION: A disc brake device 10 comprises a rotor 11; pads 12 and 13; a caliper 14; a press means 20, and a regulation means 30. The press means 20 is provided with a case 22 movable forward and backward to and from the rotor 11, and an energizing member 23 energizing the case 22 in a direction in which the case is separated from the rotor 11. The regulation means 30 comprises a rotary member 31 brought into energizing contact with the case 22; an adjuster bolt 32 threadedly engaged with the rotary member 31; a piston 33 coupled to the adjuster bolt 32 threadedly engaged with the rotary member 31; a piston 33 coupled to the adjuster bolt 32 and making contact with the pad 12; a seal member 34 making elastically frictional contact with the piston 33; and a whirl stop member 35 coupled to the adjuster bolt 32. The whirl stop member 35 is contained and held in the insertion hole 44 of a caliper 14.