A medicinal solution injection apparatus 10 includes a composite needle 12 including a needle base portion 12c, an injection needle 12d, and an adjustment needle 12e, a pressure generating portion 13 configured to discharge a compressed air, a measuring portion 14 configured to measure a filling amount and a filling speed of a medicinal solution by measuring a position of a gasket 17a of a syringe 17, and a control portion 15 configured to control the pressure generating portion 13 and the measuring portion 14 . The compressed air is introduced into a vial container 16 through an edge 12h of the adjustment needle 12e located above a liquid surface 16a of the medicinal solution in the vial container 16 (outside the liquid surface) to press the liquid surface 16a of the medicinal solution downward, so that a medicinal solution 16b is injected into the syringe 17 through an edge 12i of the injection needle 12d in the medicinal solution 16b. The medicinal solution injection apparatus 10 can accurately and efficiently inject the medicinal solution 16b of the vial container 16 into the syringe 17 while suppressing the medicinal solution 16b from foaming.