A controller according to an embodiment includes a main processing unit and a storage. The main processing unit shifts, when receiving an updating request of a control program during executing this control program, to program shifting through a restart in a state where a device power source is held. The program shifting starts an updating program for updating the control program instead of the control program. The storage is configured to be able to hold information while the device power source is held. The main processing unit causes the storage to store, before the restart, update requesting information indicating that the updating request is received, causes the storage to store a history of the restart, and performs a start determination on the updating program on the basis of the update requesting information and the history that are referred after the restart.