A bus bar unit includes: a plurality of bus bars which electrically connect coils of respective phases of a rotating electric machine and an external power source to each other, and integrally form external connection terminals; and a bus bar integral holding portion which covers parts of the plurality of bus bars and electrically insulates the plurality of bus bars to each other. Each bus bars is equal in thickness from the external connection terminal to a bus bar joining portion joined to a coil joining portion of each phase, and a width of the bus bar joining portion is wider than that of the coil joining portion.