An image processing apparatus includes: an image processing unit; a processing unit that performs predetermined processing under the control of the information processing unit; a reading unit that performs an operation of reading authentication information at intervals of a predetermined time under the control of the information processing unit; an authentication unit that authenticates a user based on the authentication information read by the reading unit under the control of the information processing unit; a permission unit that permits the predetermined processing to be performed by the processing unit on the condition that the authentication is completed by the authentication unit; and a change unit that changes the time interval for the reading unit to perform the reading operation in accordance with the status of processing to be executed.