Installation workability of a motor system 1 is improved and occurrence of a communication error between an inverter 50 and an electric portion 83 of an electric oil pump 80 due to entry of noise can be suppressed.
A motor portion 2 and the inverter 50 are adjacent to each other in a motor axial direction, at an adjacent portion, a wall of a casing of the inverter 50 on an arrow A direction side and a wall of a casing of the motor portion 2 on an arrow B direction side are shared as a barrier 3b made of the same member, and in a position that a pump portion 81 side of the electric oil pump 80 including a pump portion 81, an internal motor 82, and an electric portion 83 arranged in the motor axial direction faces the arrow A direction side, the electric oil pump 80 is disposed in the casing of the motor portion 2 and the inverter 50.