The invention discloses an exercising device. The exercising device comprises a dumbbell rod, two dumbbell balls, a power supply, a controller, pressure sensors and a protecting air bag system and ischaracterized in that the two dumbbell balls are fixedly connected to two ends of the dumbbell rod, the pressure sensors are evenly distributed on the dumbbell rod, the protecting air bag system comprises two protecting air bags and a gas generator, the protecting air bags wrap the surfaces of the dumbbell balls, the gas generator is communicated with the protecting air bags, and the pressure sensors and the gas generator are bidirectionally electrically connected with the controller. The exercising device which is a dumbbell with a protecting device has the advantages that when the dumbbell slips off from the hand and falls, the dumbbell can be wrapped by the rapidly-expanded air bags, and the dumbbell can be prevented from directly and heavily hitting a person or an object.