A high-pressure, dome-type compressor includes a DC motor 5 having a rotor 5a that uses a rare earth/iron/boron permanent magnet having an intrinsic coercive force of 1.7 MA.m−1 or greater in a rotor thereof and has a rated output or 1.9 kW or higher. The motor, which drives a compression element 3 in a casing 2, is disposed in a high pressure, high temperature area 6, which is filled with gas discharged from the compression element. An inverter 10 controls current supplied to the motor such that the motor temperature becomes equal to or less than a predetermined temperature and an opposing magnetic field generated in a stator has a predetermined strength or less. Since the magnet does not reach a high temperature and is not exposed to a strong opposing magnetic field, it is hardly demagnetized. As a result, performance of the motor and of the compressor is stable.