When a pre-determined time period has elapsed after a user access is last detected, a mobile device performs protection processing on account-related information. The mobile device includes an access detection unit that detects that a user accesses the mobile device, and a time period determination unit that determines whether or not a pre-determined time period has elapsed from a last user access time point at which the user last accessed the mobile device. The mobile device further includes a storage location acquisition unit that acquires a location in the data storage unit in which the account-related information is stored, and a protection unit that performs the protection processing on the account-related information based on the storage location of the account-related information acquired by the storage location acquisition unit, when the time period determination unit determines that a pre-determined time period has elapsed from the last user access time point.