Abstract: A caliper structure is provided for receiving a brake pad set. The structure comprises a caliper body. A cutting groove is cut at a central section of a top side thereof The cutting groove includes an upper opening and a lower opening. A diameter of the lower opening is smaller than a diameter of the upper opening. The cutting groove further includes a inclined surface arranged adjacent to the upper opening and located at any one of the inner side walls of the cutting groove. The inclined surface is inclined toward the upper opening. A normal line is extended from the inner side wall of the cutting groove having the inclined surface and an angle is defined between the normal line and the inclined surface and ranged from 11 to 32 degree.