PROBLEM TO BE SOLVED: To provide a three-way cock, capable of reducing remaining of liquid chemical on a switching passage in a columnar body, and restricting dosage error of the liquid chemical.SOLUTION: In the switching passage 8 provided in the columnar body 7, a delivery tube 5, a first introducing tube 3, and a second introducing tube 4 are communicated with one another. With this state being held, the switching passage is composed of an L-shaped through-hole 8a penetrating the columnar body 7 while bent in an L-shape to make the first introducing tube 3 and the second introducing tube 4 communicate with each other, and an outer circumferential groove 8b extended from one end of the L-shaped through-hole 8a on the side where it is communicated with the second introducing tube 4 along a circumferential surface of the columnar body 7 toward the delivery tube 5 to be communicated with the delivery tube 5.COPYRIGHT: (C)2009,JPO&INPIT【課題】円柱状体の切換路における薬液の滞留を軽減し、薬液の投与誤差を抑制することができる三方活栓を提供する。【解決手段】円柱状体7に設けられた切換路8は、導出管5と第1導入管3と第2導入管4とが互いに全て連通している状態で、円柱状体7をL字状に折れ曲がって貫通し、第1導入管3と第2導入管4とを連通させるL字状貫通孔8aと、L字状貫通孔8aの第2導入管4と連通する側の一端から円柱状体7の周面に沿って導出管5側に延設され導出管5と連通する外周溝8bとによって構成されている。【選択図】図4
