A patient's skin puncturing device, particularly for collecting a blood sample for diagnostic purposes, including a housing, a lancet slidably positioned inside the housing and having a body with a sheathed puncturing needle seated therein, and a push button positioned at the one end of the housing. Between a face end of the push button and the lancet body a drive spring is placed, and between the other end of the housing, which is provided with an opening for the puncturing needle, and the lancet body a return spring is placed. Between the housing and the lancet body is placed a lancet actuation lock, preferably in the form of interlocks of a washer. The device has a drive spring catch, preferably in the form of grabs of the washer, to preclude the drive spring from following the lancet in the puncture phase and in the retraction phase of the lancet.
