An electromagnet control device includes a current value determining circuit configured to execute a second process for determining, based on a second function, a value of the current, in the case that the magnetic flux density is to be decreased from that in a first magnetization state, and a fourth process for expanding or reducing the second function by use of a first scaling ratio for transforming it to a fourth function, and determining, based on the fourth function obtained after above transformation, a value of the current, in the case that the magnetic flux density is to be decreased from that in a third magnetization state. The current value determining circuit is further configured to determine the first scaling ratio in such a manner that the second function fits measured data that are obtained in advance by decreasing the magnetic flux density from that in the third magnetization state.