The invention relates to a syringe, which comprises a syringe, a syringe set and a push rod. The injection barrel is provided with a front end part. One end of the needle set is provided with an opening area which is transversely provided with a first card part. The push rod is slidably arranged on the syringe, and one end of the push rod toward the front end part is provided with a second card part. When the push rod slides toward the front end part, the second clamping part is buckled with the first clamping part.本創作關於一種注射器，其包括一注射筒、一針具組及一推桿。該注射筒內設有一前端部。該針具組之一端具有一開口區，該開口區橫設有一第一卡部。該推桿滑設於該注射筒，該推桿朝向該前端部之一端設有一第二卡部。其中，當該推桿朝該前端部滑移時，該第二卡部即與該第一卡部相卡扣。
