An image processing method includes an object level acquisition step of acquiring an object level set for each computer graphics object, a display step of displaying a slide bar with a movable cursor to allow a user to set a user level by manipulating the cursor, and a user level acquisition step of acquiring a user level set by the user, based on a position of the cursor of the slide bar. In addition, a rendering step renders a virtual space including each computer graphics object by rendering each computer graphics object to have its visibility attribute depending on its object level acquired in the object level acquisition step and the user level. The rendering step renders a computer graphics object with an object level less than the user level as a visible object and renders a computer graphics object with an object level equal to or larger than the user level as an invisible object, and the rendering step is repeatedly performed in response to the position of the cursor being changed by the user.