To provide an out ball handling structure of pachinko game machines that enlarges the game zone of game boards and dispenses with a complex router mounting step for the game boards and any attachment of a rear shield plate.

A support frame 5 that is a part of a game board mounting frame and is under a game board Y has in its front panel an out ball inlet and an out ball receiving part 13 projecting forward beyond it. An inner guide rail that defines a game zone 9 in the game board Y is constituted of a first guide rail 7 and a second guide rail 8, whose lower ends are extended down to the out ball receiving part 13 to lead out balls thereto. The support frame 5 has in its rear panel an out ball outlet, which is connected to the out ball inlet 13 via a guide passage.