An automatic sample injection system (1) includes at least an injector (2). The injector (2) includes a turret (10) comprising a plurality of vial receiving holes (30) that are corresponding to a plurality of types of vials having different sizes, the plurality of vial receiving holes (30) being provided on the same circumference on an upper surface of the turret, the turret being configured to rotate so that the plurality of the vial receiving holes (30) are each moved along a circumferential track, and a controller (22) configured, in a case where a sampler (4) for supplying a vial to the injector (2) is provided, to recognize a size of a target vial to be supplied at the time when the target vial is supplied from the sampler (4) and to arrange the vial receiving hole (30) corresponding to the target vial at a delivery position (P) set on the circumferential track.