A controller for an electric oil pump which is provided in parallel to a mechanical oil pump driven by an internal combustion engine as a power source of a vehicle to supply oil to a transmission for the vehicle, and which is configured to supply oil to at least a part of the transmission, the controller comprising: a determination unit configured to implement a determination mode in which the electric oil pump is rotated in advance of a request to operate the electric oil pump at a target rotational speed set to a second preoperation rotational speed, and at least when an actual rotational speed of the electric oil pump matches a second predetermined rotational speed not higher than the second preoperation rotational speed, it is determined that preoperation for the electric oil pump is completed; and a preoperation unit configured to implement a preoperation mode in which, under at least one condition that it is not yet determined that preoperation for the electric oil pump is completed, the electric oil pump is rotated at the target rotational speed set to a first preoperation rotational speed lower than the second preoperation rotational speed and the second predetermined rotational speed, and also configured to shift the preoperation mode to the determination mode when the actual rotational speed of the electric oil pump matches the first preoperation rotational speed and an actual current of the electric oil pump matches a predetermined threshold, characterized in that the preoperation unit is configured to limit restart of the electric oil pump when an integrated current value as an integrated value of current amounts supplied to the electric oil pump matches a value at which a temperature of a component of the electric oil pump reaches an allowable temperature. a determination unit configured to implement a determination mode in which the electric oil pump is rotated in advance of a request to operate the electric oil pump at a target rotational speed set to a second preoperation rotational speed, and at least when an actual rotational speed of the electric oil pump matches a second predetermined rotational speed not higher than the second preoperation rotational speed, it is determined that preoperation for the electric oil pump is completed; and a preoperation unit configured to implement a preoperation mode in which, under at least one condition that it is not yet determined that preoperation for the electric oil pump is completed, the electric oil pump is rotated at the target rotational speed set to a first preoperation rotational speed lower than the second preoperation rotational speed and the second predetermined rotational speed, and also configured to shift the preoperation mode to the determination mode when the actual rotational speed of the electric oil pump matches the first preoperation rotational speed and an actual current of the electric oil pump matches a predetermined threshold, characterized in that the preoperation unit is configured to limit restart of the electric oil pump when an integrated current value as an integrated value of current amounts supplied to the electric oil pump matches a value at which a temperature of a component of the electric oil pump reaches an allowable temperature.