A cooling unit for integrating into a housing, especially a control box, including an assembly plate which is embodied to receive electrical components and has at least one cooling channel through which a coolant flows or is to flow. This invention provides the cooling unit with a compact structure and a high cooling performance. Thus, an air cooling unit with a fan is provided on the assembly plate for cooling warm air accumulated in the housing due to dissipated heat. The fan is used to guide the warm air along the assembly plate for cooling purposes.