Abstract: The invention relates to a medical instrument with a hollow instrument canal that is configured inside a housing and can be closed by means of at least one valve body and rotated into open position by means of an instrument inserted into the instrument canal. The at least one valve body is configured as a flap consisting of an essentially non-bendable material mounted on the housing so that it can be rotated by means of an elastic, bendable connecting element configured as a wire spring in such a way that the valve body is pre-tensioned in the closed direction. A medical instrument with a valve body of simple construction, which insulates reliably, is distinguished according to the invention in that the connecting element on the one hand is secured on the housing and on the other hand carries the valve body, so that the connecting element can be secured in a ring groove configured in the housing.