To provide the novel form of a game ball attracted and guided by a magnet without leaving a mark to be an indicator for guessing the position of the magnet that is invisibly hidden and provided.

A game ball transfer device 40 includes a rotating body 41 as a movable member which includes a magnet 42 on the outer side and can perform a prescribed operation, and a cover body 45 as a shield member which makes the magnet 42 invisible from the outside and is operated or stands still so as not to be synchronized with the prescribed operation of the rotating body 41, and the magnet 42 attracts and transfers a game ball 10 via the cover body 45.