PURPOSE: To easily and quickly replace pads for a brake caliper by providing a lever for deforming a quadric crank chain into a parallelogram or a parallelogramic shape and quickly enlarging the interval between a pair of brake pads by a pair of opposed plates.

CONSTITUTION: When a lever is drawn in an appropriate direction, an upper link 2u which is slidingly connected to a central long hole 48 in the longitudinal direction of the lever 8 via a shaft 19a engaged with the upper rink 2u moves parallel by changing intervals with the lower link 2d. At the same time, left and right links 41, 4r are tilted so that elliptic cams 26 provided in the respective links 41, 4r are also tilted and the interval between a pair of opposed plates 38, 38 made sliding contact therewith is changed. Therefore, a pair of opposed plates 38, 38 are inserted between a pair of brake pads 54, 54 with their intervals narrowed and when the lever 8 is drawn in the opposed direction, the interval between the opposed plates 38, 38 is widened so that the pad replacement is easily performed.