PROBLEM TO BE SOLVED: To solve a problem that a rubber cap (1) comes out with a plug member (4) from a mouth (22) of a vial when removing the plug member (4) as to a vial cap comprising a socket member (3) to be mounted on the mouth (22) of a vial (2) closed with a rubber cap (1), and a plug member (4) which is inserted in the socket member (3) to be engaged with, wherein the socket member (3) has a tubular part (31) upwardly extending from the mouth (22) of the vial (2) when it is mounted, and the plug member (4) fixes the rubber cap (1) by contacting its tip end (41) to the rubber cap (1) of the vial (2) when it is inserted in the tubular part (31) of the socket member (3) and is engaged with the socket member (3).SOLUTION: A rubber cap (1) is prevented from coming out from the tubular part (31) by forming a narrow part (34) in the tubular part (31) of a socket member (3).COPYRIGHT: (C)2013,JPO&INPIT【課題】ゴム栓(1)で閉止されたバイアル(2)の口部(22)に取り付けられるソケット部材(3)と、ソケット部材(3)に挿入されて係合するプラグ部材(4)とからなり、ソケット部材(3)は取り付け時にバイアル(2)の口部(22)から上方に延びる管状部(31)を備え、プラグ部材(4)はソケット部材(3)の管状部(31)内に挿入されてソケット部材(3)と係合した時に自身の先端部(41)をバイアル(2)のゴム栓(1)に当接させることによりゴム栓(1)を固定するバイアルキャップにおいて、プラグ部材(4)の取り外しの際にゴム栓(1)がプラグ部材(4)と一緒にバイアルの口部(22)から外れる問題を解決する。【解決手段】ソケット部材(3)の管状部(31)内に狭窄部(34)を設けてゴム栓(1)が管状部(31)から抜け出るのを防止する。【選択図】図1
