A quantitative syringe-type ejector capable of ejecting the contents packed in one syringe in small quantities is provided. The quantitative syringe-type ejector includes a syringe (10) and a plunger (P). The plunger (P) includes a piston holding member (30) and a plunger operation member (40). The piston holding member (30) has at least one arm (33) having: a slide projection (34) slidable on an inner peripheral surface (10f) of the syringe (10); and a lock projection (35) to be releasably locked to a back end (10e) of the syringe (10). The plunger operation member (40) has a lock part (47) to be releasably locked to the back end (10e) of the syringe (10).