A mobile robot that is fitted with a camera and can be controlled from a remote terminal such as a mobile phone moves about in an event site to detect and track a moving object such as a visitor and entertainer. Because the camera along with the robot itself can change its position freely autonomously and/or according to a command from the mobile terminal, a desired frame layout can be accomplished by moving the position of the robot. Therefore, the operator is not required to execute a complex image trimming process or other adjustment of the obtained picture image so that a desired picture can be obtained quickly and without any difficulty. If the user is allowed access the managing server, the user can download the desired picture images and have them printed out at will. Also, because the selected picture images can be transmitted to the managing server, the robot is prevented from running out of memory for storing the picture images.