To provide a Pachinko game machine for preventing the deterioration of operation property in a ball return prevention device during a game.

The ball return prevention device 16 includes: a body member 32; and a gate member 31 turnably and pivotally attached to the body member 32 via a support shaft 36. The body member 32 includes: a press fitting part 45 forming a press fitting hole 44 to press-fit the distal end part of the spindle 36; a cover part 42 positioned on the front side of the press fitting part 45; and an attachment base part 39 attached to the board surface of a game board 5; and a positioning projection 43 to be fitted to a positioning hole 49 formed in the game board 5. The gate member 31 includes: a pivotal support hole 37 for inserting the support shaft 36 therein; and a weight part 35 for biasing the gate member 31 to a closing position. The support shaft 36 is inserted into the pivotal support hole 37, the pivotal support hole 37 and the press fitting hole 44 are serially arranged in a front and a rear. Then, the distal end part of the support shaft 36 is press-fitted and fixed to the press fitting hole 44.