A frequency converter includes a housing, which is designed and envisaged for the peripheral assembly on an electric motor. The base of the housing is provided in the middle region on the outside with longitudinal ribs and is connected to heat-producing components of the power circuit of the frequency converter, is provided in outer regions with cooling ribs which are arranged on the outside transversely or obliquely to the longitudinal ribs, and on the inside is connected in a heat-conducting manner to heat-producing components of the input circuit and/or output circuit.