The present invention concerns a blood withdrawal device comprising a one-piece cap and lancet and a painless impulse generator. The object of the present invention is to withdraw blood painlessly and to reduce a risk of a secondary infection. In order to achieve the object of the present invention, the blood withdrawal device of the present invention comprises a cap, a hollow body and a painless blood withdrawal device. The cap comprises a one-piece cap and lancet within which a lancet is movably combined and a hollow body for a detachable connection with a painless impulse generator or a main body of a blood withdrawal device. The hollow body comprises open ends on both side of the body thereby allowing the lancet to be detachable and the movable axis to be inserted within the body. The painless impulse generator is connected with the main body of the blood withdrawal device through a means for connecting with the main body of the blood withdrawal device defined at one side of the body thereby allowing the movement of the lancet needle and the cap by the movable axis. Therefore painless blood withdrawal is possible.
