A control device includes an estimation module configured to repeatedly calculate an angle estimation value correlated with a magnetic pole position of a rotating electric machine, and a storage module configured to store the angle estimation value. The estimation module includes a response information calculation module configured to calculate response information indicating a current change resulting from a change in an output voltage to the rotating electric machine or a voltage change resulting from a change in an output current to the rotating electric machine, a coefficient calculation module configured to calculate an interference coefficient correlated with electromagnetic mutual interference between coordinate axes of an orthogonal coordinate system of the rotating electric machine based on a past angle estimation value stored in the storage module, and an angle calculation module configured to calculate an angle estimation value based on the response information and the interference coefficient.