An exercising device includes a base, a driving unit and a limit cap. The base has an upper surface provided with two toothed racks, a first contact switch and a second contact switch and a lower surface provided with an antiskid member. The limit cap has an elongate slideway. The driving unit includes a housing, a rotation shaft, a motor, two driven gears, two handgrips, and a control switch. When the driving unit touches the first contact switch or the second contact switch, the motor is controlled to change the rotation direction of the rotation shaft. Thus, the slideway limits the moving direction of the driving unit to prevent the driving unit from being deflected sideward during movement. In addition, the base will not slip from the ground by provision of the antiskid member.