To provide an oil feed nozzle to adapt to the grease nipple of a rolling guide unit and simply and accurately inject oil against the grease nipple.

An oil feed nozzle 1 mounted on a grease feeding means, such as a grease gun, through a pipe coupling 4 comprises a conduit 2 consisting of a fine tube; a nipple 5 arranged on the tip side of the conduit 2; a mouthpiece 6 arranged further on the tip side of the nipple 5; and a check valve 7 disposed between the nipple 5 sand the mouth piece 6 and closing the opening 12a of the grease passage 12 of the nipple 5. During completion of a feed of grease, the check valve 7 holds grease in the oil feed nozzle 1 and prevents sagging of grease through the mouthpiece 6. The port edge part 17 of the recessed spherical surface of an oil injection port 16 is joined in a liquidtight manner to the periphery of the oil feed port of a grease nipple.