Disc brake device

A disc brake device, comprising:

• a rotor;
• a caliper body;
• a slide pin fixed to the caliper body;
• a support bracket having an insertion hole configured to place the slide pin;
• and
• a covering member having a pleat and covering a portion of the slide pin exposed outside the insertion hole of the support bracket;
• a first pad fixed to the caliper body and positioned to face the rotor on a first side of the rotor;
• a second pad positioned to face the rotor on a second side of the rotor;
• and
• a piston configured to push the second pad toward the rotor,
• wherein the insertion hole of the support bracket and the covering member enclosing the portion of the slide pin form an internal space such that the internal space includes a first internal space in the pleat of the covering member and a second internal space excluding the first internal space from the internal space and that a ratio of a first volume of the first internal space to a second volume of the second internal space is set within a predetermined range.