A connector (1) that can be connected to a first container and a second container (20) to transfer a liquid between the first container and the second container (20) includes a first connecting portion (3) that is engageable with the first container and a second connecting portion (4) that is engageable with the second container (20). The second connecting portion (4) is integrally provided with an engagement portion that is engageable with the second container (20) and a needle-like portion (7) for piercing into the second container (20). Thus, it is possible to prevent a container from falling off during liquid transfer. Also, since the needle-like portion (7) is integral with the second connecting portion (4), connection to the second container (20) is facilitated.
