A battery pack includes: a battery; a notification unit configured to notify that a fully charged state is reached; a determination unit configured to determine whether the fully charged state is reached; a processing unit configured to execute a full charge process if the fully charged state is determined, the full charge process being one of causing the notification unit to make a notification and maintaining a possible state, in which making a notification is possible; and a factor detection unit configured to detect occurrence of a predetermined increase factor during execution of the full charge process, the increase factor leading to increase in a chargeable capacity of the battery as compared with the time when the fully charged state is determined. The processing unit stops the full charge process if occurrence of the increase factor is detected during execution of the full charge process.