A safety scalpel comprising an elongated central body having opposite ends (2, 3) for respective lancets, wherein the elongated central body comprises a retractable lancet system connected at each of its opposite ends (2, 3), wherein the retractable lancet system comprises: - a protection member having a slot with stop recesses (10, 11), a distal opening and an opposite closed end that is connected to the elongated central body, and concentric thereto; - a prismatic guide concentric to the elongated central body that is located inside the protection member; and - a lancet holding member consisting of: a distal part in the form of a prismatic member in which the lancet is frontally inserted, and a proximal part formed by two parallel arms (25, 26) having an end integral with the prismatic member, a first arm of them being slidable in contact with the prismatic guide and a second arm carrying on a button protruding from the slot of the protection member and being provided with retaining elements intended to be received into the stop recesses (10, 11) of the slot. wherein the elongated central body comprises a retractable lancet system connected at each of its opposite ends (2, 3), wherein the retractable lancet system comprises: - a protection member having a slot with stop recesses (10, 11), a distal opening and an opposite closed end that is connected to the elongated central body, and concentric thereto; - a prismatic guide concentric to the elongated central body that is located inside the protection member; and - a lancet holding member consisting of: a distal part in the form of a prismatic member in which the lancet is frontally inserted, and a proximal part formed by two parallel arms (25, 26) having an end integral with the prismatic member, a first arm of them being slidable in contact with the prismatic guide and a second arm carrying on a button protruding from the slot of the protection member and being provided with retaining elements intended to be received into the stop recesses (10, 11) of the slot. - a protection member having a slot with stop recesses (10, 11), a distal opening and an opposite closed end that is connected to the elongated central body, and concentric thereto; - a prismatic guide concentric to the elongated central body that is located inside the protection member; and - a lancet holding member consisting of: a distal part in the form of a prismatic member in which the lancet is frontally inserted, and a proximal part formed by two parallel arms (25, 26) having an end integral with the prismatic member, a first arm of them being slidable in contact with the prismatic guide and a second arm carrying on a button protruding from the slot of the protection member and being provided with retaining elements intended to be received into the stop recesses (10, 11) of the slot. a distal part in the form of a prismatic member in which the lancet is frontally inserted, and a proximal part formed by two parallel arms (25, 26) having an end integral with the prismatic member, a first arm of them being slidable in contact with the prismatic guide and a second arm carrying on a button protruding from the slot of the protection member and being provided with retaining elements intended to be received into the stop recesses (10, 11) of the slot.