Abstract: A generating device for an exercising equipment includes a power source, a speed increasing unit and a generating unit. The generating unit includes a rotor, a stator located in the rotor and a driven member secured on the rotor and provided with a driven gear. The speed increasing unit includes a drive member having a first portion rotated by the power source and a second portion provided with a drive gear and a plurality of transmission gears each intermeshing with the drive gear and the driven gear. The drive gear has a diameter greater than that of each of the transmission gears so that the rotation speed of each of the transmission gears is greater than that of the drive member to increase the rotation speed of the rotor and to enhance the generating efficiency of the generating unit.