There is provided a dispenser in which an operation load of a plunger is stable and contents of the dispenser do not leak out after pressing operation is interrupted. The invention provides a dispenser comprising a syringe body (1) having a space for filling contents equipped with a extruding nozzle at the front end thereof, a plunger (2) slid, by pressing force applied thereto, in the syringe body (1) to extrude the contents in the filling space (m) from the tip of the extruding nozzle, an O-ring (3) placed in an annular groove (2) formed in the front end section of the plunger and slidable on the inner wall surface of the syringe body (1), wherein the annular groove (2c) is formed as a defined recess having a flat bottom wall over its entirety a plurality of projections or grooves (4) are formed on the sidewall of the annular groove (2c) with intervals therebetween so that restoring force of the O-rings (3) causes the plunger (2) to slide to the opposite direction of the press-in direction, thus inducing back suction of contents.
