Abstract: A multi-vial adapter includes an adapter body including at least two body parts, which are connected to each other at a certain angle, a head part, which protrudes upward from a connection portion between the body parts, and at least two spike parts, which extend downward from the body parts, respectively, at positions spaced a certain distance from the connection portion, and at least two adapter caps which are physically fastened and fixed to the body parts, respectively, and through which the spike parts respectively pass. The adapter body is formed by an injection molding process such that the head part, the body parts, and the spike parts are integrated with each other, and a liquid drug flow path that guides the movement of a liquid drug from the respective spike parts to the head part via the respective body parts may be formed inside the adapter body.