Injecting machine includes a conveyor having a surface for conveying meat pieces in a forward direction； first and second injection heads consecutively arranged over the conveyor relative to the forward direction and with the second injection head installed at a higher level over the surface than the first injection head； a plurality of needles mounted on each injection head, each needle having a longitudinal inner passage, at least one inlet opening in communication with the inner passage and a plurality of outlet openings in communication with the inner passage； head driving device for alternately reciprocating the first and second injection heads between an upper position, enabling the meat pieces to pass, and a lower position, in which the lower needle portions are stuck into the meat pieces； and brine supplying device for supplying brine to the needles when the injection heads are in the lower position.
