An electric motor system includes a motor, a hydrodynamic air bearing that rotatably supports a shaft of the motor, a power conversion circuit that provides a drive current to the motor, and a controller including a life evaluation module that evaluates a life of the air bearing. The life evaluation module has a data input unit that obtains rotation speed history data which is a time history of a rotation speed of the motor, a sliding distance acquisition unit that obtains, using the rotation speed history data, a sliding distance when the shaft is in a state of rotating while being in contact with the air bearing, and an evaluation value calculation unit that evaluates the life of the air bearing using the sliding distance.