To provide a Pachinko machine capable of maintaining a reverse flow preventive function for game balls for a long period of time while saving space.

A ball return preventive member 41 in which an open/close valve 41b and a weight 41c are provided is turnably journaled inside a recess S of a base member 43, and an engagement pin 41d projecting on a side surface of the weight 41c is inserted into a guide groove 39e formed through a side plate 39b of a body case 39. When a game ball is shot from a shooting device 23 toward a play area 8, the game ball rises through a shooting guide passway 34 to be brought into contact with the open/close valve 41b. After that, the game ball pushes off the open/close valve 41b with the contact force, and enters the play area 8, whereby the ball return preventive member 41 is turned to form the maximum opening angle. After that, the ball return preventive member 41 is immediately turned to return in the reverse direction with the energization force of the weight 41c, and when the engagement pin 41d abuts to one end of the guide groove 39e, the ball return preventive member 41 stops again in an attitude with the open/close valve 41b facing an exit of the shooting guide passway 34.