Patent ID: 7410478

Claim:
A safety syringe, comprising: a syringe barrel including a barrel body with a front opening, a rear opening, a front end wall and a rear end wall, wherein a cross-sectional area of said front opening is smaller than a cross-sectional area of said rear opening, a spacer portion is disposed integrally within said barrel body and is penetrated by said front opening; a flexible holder-supporting seat being disposed movably within said syringe barrel and on said spacer portion, wherein said flexible holder-supporting seat includes a central hole formed therethrough; a needle unit including a needle holder and a needle penetrating said needle holder, said needle unit is disposed movably within said front end wall, said needle holder being sleeved by said central hole of said flexible holder-supporting seat on said spacer portion, wherein a rear opening is formed in said rear end of said needle holder, said needle penetrates said needle holder and said spacer portion and is projected from said front opening; a plunger including a front end with a front opening and an inward flange, a rear end and a plunger body formed between said front end and said rear end, a cross-sectional area of said front opening being larger than an external diameter of said needle holder, said plunger being disposed movably within said syringe barrel; and a flexible sealing member sleeved by said inward flange to seal said front opening of said plunger, said flexible sealing member combining with said needle unit after said plunger being pushed to be close to said flexible holder-supporting seat, said flexible holder-supporting seat being sleeved on said spacer portion, and then said needle unit being released from said flexible holder-supporting seat due to said plunger, wherein said flexible sealing member is propped by said needle holder, and then said flexible sealing member is released from said inward flange to be automatically retracted into said plunger body due to a pressure.