Provided is a clutch unit in which an output-side outer ring member is attached to a base plate without welding. A clutch unit (100) includes an output-side clutch (60) and a housing (11) that accommodates the output-side clutch (60). The output-side clutch (60) includes an output-side outer ring member (62). The output-side outer ring member (62) and the housing (11) have an engagement protrusion (62s) and an engagement groove (11s) that engage with each other to restrict relative rotation therebetween.