A circuit breaker housing for holding a switching device unit and a number of connection contacts for a connection line and/or a busbar. The housing has a first housing part and a second housing part. In the joined, assembled state, the housing parts form a front side and a rear side opposite said front side and at least one connection side and end faces located opposite one another. A holding chamber for a connection module having one of the connection contacts is provided on the front side and/or on at least one of the connection sides.