The contracting device has a contracting band (10) definable around a body part and a closure device (30), by which the contracting band is lockable in its tensioned condition to a loop. A voltage indicator (101) is provided for detecting a voltage condition of the contracting band. The voltage indicator is formed in a manner such that a defined voltage condition is seen by a user. The voltage indicator is arranged on the outer side of the contracting band, where the outer side faces away from the body part in the use condition.
