A floating aquatic stair stepper having a frame with support bars, two extension legs secured to the frame and two foot placement steps movably secured to each extension leg. Circumferences of the blade holes of the frame are bent toward the inner blade so as to provide hair lifting portions having rounded portions in the frame, and the frame provided with the hair lifting portions is located closer to a skin than to a surface of the inner blade on a skin side. During the H period of the signal, the switch is closed, and the output value of an amplifier is input to a capacitor. For example, the adhesion reinforcing portion is a notch portion which is cut and formed in the opposed side surfaces. In order to offer active anti-blocking protection for vehicle passengers, the anti-blocking devices are formed, respectively, by a strip-shaped switching device which interacts with respective guiding rail and which is connected to the control element of a cover element drive.