A stepping exercise apparatus includes a body, a crank pedal mechanism and a foot support device. The crank pedal mechanism is mounted in the body and includes a crank shaft and two pedals mounted respectively on two ends of the crank shaft. The foot support device is connected to the body to support and includes two feet, two positioning locks and two stabilizer bars. The feet are respectively and pivotally connected to body between a folded position and an unfolded position. The positioning locks are respectively mounted between the body and the feet to respectively lock the feet with the body when the feet are respectively kept in the unfolded position. The stabilizer bars are respectively and transversely connected to the feet.