The invention discloses a wire feeding mechanism which comprises a front base, a rear base, a left pressing arm, a right pressing arm, four sets of transmission assemblies and a pressure adjusting component, wherein each set of transmission assembly comprises precision bearings, a wire feeding gear, a shaft lever, a wire feed roller and fixing devices; each feeding gear is respectively connected with the left pressing arm and the right pressing arm through the corresponding precision bearings; each shaft lever is connected with the corresponding wire feed roller through the corresponding fixing devices so as to drive the corresponding wire feed roller; two sets of the transmission assemblies are respectively assembled in the left pressing arm and the right pressing arm; the other two sets of the transmission assemblies are respectively assembled in the front base and the rear base; pressure adjusting graduations are arranged on the pressure adjusting component and the pressure adjusting component is arranged in the front base and realizes wire feeding pressure output adjustment through adjustment of an internal fastening spring. According to the wire feeding mechanism provided by the invention, power provided by a wire feeding motor is precisely output to welding wires through four-roller transmission, so that stable output of the welding wires is ensured, a good welding effect is realized and the production efficiency is improved.