A kind of syringe of what is closed in this creation comprising an injection tube, a needle set group and a push rod. The injection tube includes that injection tube one end collects section, which encloses one room of structure. The needle set group includes an adapter, a needle base and a syringe needle, the adapter separatably sets what, and this collects in section and internal is equipped with a buckle slot, the needle base group connects the what adapter, the syringe needle sets the what other end of the needle base far from the adapter, the outer wall of the adapter is equipped with a coding, the concaveconvex structure which is marked by the mold that manufacture shapes the adapter. The push rod includes an elastic piston and an ejector, which slippingly sets inside the what injection tube, and one end of the ejector, which wears the what elastic piston and extends, is equipped with a 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。該注射筒包括一位於該注射筒一端之收束段，該注射筒圍構一容室。該針具組包括一轉接頭、一針基及一針頭，該轉接頭可脫離地設於該收束段中且內部設有一卡扣槽，該針基組接於該轉接頭，該針頭設於該針基遠離該轉接頭之另一端，該轉接頭之外壁設有一編碼，該編碼係由製造成形出該轉接頭之模具所刻印之凹凸結構。該推桿包括一彈性活塞及一推頂件，該彈性活塞可滑移地設於該注射筒內部，該推頂件之一端穿設於該彈性活塞且延伸設有一卡扣部。
