For realistic mounting simulation of an image device, a mobile device according to one embodiment comprises: a display; a camera for photographing a space in which the image device is to be mounted; a user interface unit for receiving a user's input; and a control unit for controlling the display so that an image of the space photographed by the camera is displayed together with a grid, and controlling the display so that a virtual image of the image device, of which the size has been adjusted in response to the user's input, is displayed on the grid.