The present invention relates to an injection port structure of a granular fertilizer injector. More specifically, a lid part 110 in the form of a semicircular tube 120 is formed at a tip end, a circular tube 120 is formed at a rear end part, A main pipe 100 having an annular ring 130 protruded along an outer periphery of the pipe 120 and having a male screw portion 131 formed on an outer periphery of the annular ring 130 The tip end portion of the beveled surface 210 is inclined with an oblique angle and the discharge hole 220 is formed at the outer circumferential edge of the beveled portion 210 along the outer circumferential edge. And an annular ring 230 is protruded along the outer periphery of the annular ring 230. A coupling hole 231 is formed in the annular ring 230 at a position aligned with the exhaust hole 220, An annular ring 230 formed at the center and a ring-shaped annular ring 210 formed at the center of the main pipe 100 are formed in such a manner that the lid part 110 of the main pipe 100 is inserted and the leading end of the lid part 110 is positioned adjacent to the discharge hole 220, A coil spring 240 is installed between the coil spring 240 and the cover 130 and the discharge hole 220 is opened and closed by the coil spring 240 and the cover 110 of the main tube 100 A female thread portion 310 is formed at the rear end of the main pipe 100 so as to be screwed with the male thread portion 131 of the annular ring 130 of the main pipe 100. An annular stopping protrusion 320 protrudes from the distal end portion along the inner circumference, And the coupling pipe 300 configured to prevent the release of the operation tube 200 by configuring the rear surface of the stopping jaw 320 to abut the front surface of the annular ring 230 of the operation tube 200, When injected into the ground, the discharge hole of the working pipe is injected in a closed state, thereby preventing the earth from entering the inside of the working pipe, and advantageou
