Disclosed is a blood lancet device including a shaft which is driven toward a lancet, a blood collection button for launching the shaft, a tensioning unit for tensioning the shaft, and a depth-adjusting unit for adjusting a puncturing depth of a needle of the lancet. The shaft is provided inside a body, tensioned by operation of the tensioning unit, and combined with the lancet at a front end thereof. The blood collection button is provided outside the shaft, elastically supported by an inside surface of the body, and arranged to protrude outward from an end of the body. The tensioning unit is arranged in line with the blood collection button. The depth-adjusting unit is combined with a front end of the body in a rotatable manner, has a hole provided in a center portion of a front surface thereof, and covers the lancet.
