The pedal comprises a pedal body (2) mounted rotatably on a pedal axle (3) and provided with a retainer (7 to 10) of an engagement member fixed below a bicycle shoe, the retainer (7 to 10) comprising a first pair of arches (7, 8) mounted fixedly and a second pair of arches (9, 10) mounted pivoting between the fixed arches (7, 8). A resilient return (12, 13) acts on the pivoting arches (9, 10) to urge them toward a position of retaining the engagement member between a fixed arch (7, 8) and a pivoting arch (9, 10) following relative angular spacing apart of these latter by said engagement member against the action of the resilient return (12, 13). The pivotal axis of each pivoting arch (9, 10) is eccentric to the axis of rotation (A-A) of the pedal axle (3).