Provided is an input device for a billiard game comprising: a simulative ball provided as an object to be shot by a player; a link portion having a ball axis on which the simulative ball is mounted; a support portion for movably supporting the link portion; and a sensor for outputting a signal that corresponds to an operation of the link portion, wherein at least either one of rotational motion of the simulative ball around an axle of a ball axis and linear motion of the simulative ball in a predetermined range along an axial direction of the ball axis is permitted.