A syringe is provided, including a syringe barrel, a needle set and a push rod. A front end part is provided in the syringe barrel. An end of the needle set has an open area, the open area is transversely provided with a first snap part. The push rod is slidably disposed within the syringe barrel, and an end of the push rod facing the front end part has a second snap part. When the push rod is slidingly moved to the front end part, the second snap part is engaged with the first snap part.