A multifunction printer includes a display section, a web browser section for operating in accordance with software for a web browser, and a second web server section for operating in accordance with software for a web server. The web browser section causes the display section to display an operation window indicated by image data received from a first web server section, and notifies the second web server section of a control instruction to control the multifunction printer, which instruction is entered into the operation window. The multifunction printer further includes a device control section for controlling the multifunction printer in accordance with the control instruction of which the web browser section notifies the second web server section. This allows controlling the multifunction printer via the operation window received from an information processing apparatus even when a firewall is constructed between the information processing apparatus and the multifunction printer, and also allows easily customizing the operation window.