This disclosure concerns a medical device and a method for its production, wherein the device comprises a cannula having an elongated hollow shaft and a sharp tip provided at a distal end of the shaft, wherein the shaft is formed as a bent part from a sheet material and confines an interior passage which has a lateral slit opening, and wherein the shaft has at least one longitudinal pre-bending channel provided in the sheet material, wherein the thickness of the sheet material is reduced along the pre-bending channel and a sidewall of the shaft is folded over the pre-bending channel.