An electric compressor is provided with a compression mechanism, an electric motor, a motor housing, discharge housing and an intermediate pressure housing. The compression mechanism has a compression chamber and is driven by the electric motor. The motor housing accommodates therein the electric motor and the compression mechanism and formed therein an injection port. The discharge housing has therein a discharge chamber into which compressed refrigerant is discharged. The intermediate pressure housing has therein an introduction port for introducing intermediate pressure refrigerant from an external refrigerant circuit and a communication passage that provides communication between the introduction port and the injection port of the motor housing. The motor housing, discharge housing and the intermediate pressure housing has a bolt fastening hole, and a bolt is inserted in the bolt fastening holes to integrally fix the motor housing, discharge housing and the intermediate pressure housing.