To provide a syringe with a needle storage mechanism in which the needle storage mechanism is not activated before use. A safety syringe including an injection barrel 1 having a connecting portion 11 at the distal end and an opening at the proximal end thereof, a needle assembly B having an injection needle 5 and a needle base 6 fixed to the proximal end of the injection needle 5 and being connected to the connecting portion 11, a gasket 2 provided liquid-tightly and slidably in the injection barrel, a plunger 3 being connected to the proximal end of the gasket 2 and joining means 21 provided at the distal portion of the gasket 2 or the plunger3, and joined means 61 provided at the proximal portion of the needle base 6, wherein a joint preventing means 90 which prevents the joining means 21 and the joined means 61 from joining unintentionally before use, and allows joining to each other when in use is provided.