Provided is an image forming apparatus that allows a remote operation terminal to operate an image processing apparatus connected by SIP. On this account, the image forming apparatus (100) connected to the remote operation terminal (300) by SIP includes a remote operation-request message receiving part that receive a remote-operation request message from the remote operation terminal (300), a remote-operation response message transmitting part that transmits a remote-operation response message in response to the remote-operation request message, and an operation-screen information transmitting part that transmits operation screen information of the image forming apparatus (100) to the remote operation terminal (300) in accordance with the communication condition of the communication session when an SIP-based communication session is established between the remote operation terminal (300) and the image forming apparatus (100).

When an image forming apparatus satisfies a condition to shift it to a power saving state, if a specific function that needs to respond to an inquiry from an external apparatus within a predetermined time is set, a power control unit shifts the image forming apparatus to a first power saving state in which power is supplied to a control unit configured to respond to the inquiry, and if the specific function is not set, shifts the image forming apparatus to a second power saving state in which no power is supplied to the control unit.