An unit (317, 318) acquires identification information from a camera (101R) (left camera 101L). The unit (303, 312) checks a connection state based on the identification information, and determines the subsequent operation. A unit (305) transmits position and orientation information of the camera (101R) to an apparatus (206). A unit (308) outputs a composite image of a virtual space image generated based on the position and orientation information and a captured image input by a unit (302) to an HMD (100). A unit (313) calculates the position and orientation of the camera (101L) using position and orientation relationship information and the position and orientation information. An unit (316) outputs a composite image of a virtual space image generated based on the position and orientation of the camera (101L), and a captured image input by a unit (311) to the HMD (100).