To reduce slide resistance of a slide piece in a crossing part of a reciprocating spiral groove formed in a guide shaft body and to induce the slide piece smoothly in a product pushing-out device.

Linear parts 35b are formed on both sides in the longitudinal direction in a slide piece 35 to be assembled on a pusher travelling body reciprocating and travelling along a lead screw in a condition of engaged with a reciprocating spiral groove of the lead screw. A length L of the linear part 35b is larger than a groove width in a crossing part of two spiral grooves constituting the reciprocating spiral groove. For this reason, in a process in which the slide piece 35 passes the crossing part in which a wall face disappears, the linear part 35b is guided to a wall face of the groove on a front side to keep the slide piece 35 at the attitude in which it is along the groove direction until the linear part 35b is guided to a wall face of the groove at arrival destination.