The invention relates to a muscle stimulation device comprising a handle bar with a first and a second end, a motor which is arranged in a cavity in the handle bar and is coupled by means of a motor shaft to at least one eccentric body in order to set the muscle stimulation device vibrating by an unbalance of the eccentric body. According to the invention the eccentric body/ies has/have a common center of mass, which is at a different distance from the first end of the handle bar than it is from the second end of the handle bar. The invention furthermore relates to an exchangeable head for such a muscle stimulation device.