Patent ID: 8702675

Claim:
A vial adapter comprising: a fitting portion, which has a flexible arm portion provided with a claw for engagement with a head portion of a vial and which can be fitted onto the head portion of the vial; and a hollow needle, which is disposed inside the fitting portion coaxially with the fitting portion, and which, when the fitting portion is fitted onto the head portion of the vial, pierces a stopper formed of an elastic material and that is mounted to the vial, and a hollow, tubular reduced-diameter adapter that can be mounted inside the fitting portion, wherein: a first reduced-diameter fitting portion, which is capable of being fitted onto a vial head portion having a first outside diameter smaller than a basic outside diameter with which the fitting portion can cope, is provided on one end side of the reduced-diameter adapter, and a first claw portion is provided on the inner circumferential side of the first reduced-diameter fitting portion; a second reduced-diameter fitting portion, which is capable of being fitted onto a vial head portion having a second outside diameter smaller than the first outside diameter, is provided on the other end side of the reduced-diameter adapter, and a second claw portion is provided on the inner circumferential side of the second reduced-diameter fitting portion; the vial adapter is provided therein with an adapter end insertion portion into which an end portion of the reduced-diameter adapter is inserted when the reduced-diameter adapter is mounted to the fitting portion; and the reduced-diameter adapter can be mounted to the fitting portion in an orientation for enabling insertion of the first reduced-diameter fitting portion into the adapter end insertion portion, and can be mounted to the fitting portion in an orientation for enabling insertion of the second reduced-diameter fitting portion into the adapter end insertion portion.