To reliably level game balls flowing in stacked without causing clogging while shortening the length and reducing the height of a ball-flowing-down gutter for expanding a game area within the surface of a game panel.

A ball leveling mechanism is provided to the ball-flowing-down gutter 2 of a game machine and levels the game balls B flowing in from an upstream side to flow out to a downstream side. The mechanism is provided with a ball leveling member 3 which has a guide surface 31a extending in the longitudinal direction of the gutter 2 and tilted upward in the upstream direction and which the game balls B in a top stage flowing in from the upstream side abuts on. The ball leveling member 3 is supported by inserting a shaft portion 37 into an oblong hole 36 such that the guide surface 31a is rotate-movable forward and inversely in a vertical direction, and movable linearly in the vertical direction.