Abstract: A footstep exerciser comprises a base frame assembly to be installed on a floor, a crank shaft rotatably supported on the frame assembly and provided at the opposite ends thereof with a pair of crank pedals to be stepped by a user, a flywheel of magnetic material fixedly mounted on the crank shaft for rotation therewith in a vertical plane, a pair of vertically spaced movable permanent magnets arranged adjacent the flywheel to be moved toward and away from the flywheel in a vertical plane parallel with one face of the flywheel, a support mechanism mounted on a portion of the frame assembly for supporting thereon the permanent magnets in such a manner that the permanent magnets are opposed to the one face of the flywheel with a predetermined slight clearance when moved toward the flywheel, and an actuation device operatively connected to the support mechanism for moving the permanent magnets toward and away from the flywheel and for retaining the same in their moved positions.