A protective cover type safety device for syringes includes a first buckle seat, a second buckle seat which can be engaged with the first buckle seat, and a protective cover which is pivotably connected with the first buckle seat. The first buckle seat and the second buckle seats are clamped and positioned to a needle seat of a syringe, and the protective cover is able to swing between a first position and a second position, and limited at a third position. The protective cover at the third position covers a needle body of the syringe to prevent the needle body from being exposed or piercing or hurting people.