An inverter controller includes a processing circuitry. The processing circuitry is configured to obtain a command rotation speed transmitted repeatedly from outside of the inverter controller, count a command obtaining interval that is a period from a point in time where an old command rotation speed was obtained to a point in time where a new command rotation speed is obtained, set a target acceleration of the electric motor when the command rotation speed has been obtained, and control the inverter circuit such that the electric motor rotates at the set target acceleration. The processing circuitry is configured to calculate a command acceleration based on the counted command obtaining interval and the new command rotation speed, the command acceleration being set as the target acceleration.