An oiling nozzle comprising: a feed-in section; a feed-out section; and a middle section located between the feed-in section and the feed-out section and configured to be in contact with a yarn, wherein the middle section includes: an oil discharge hole located at a position on the feed-in section side; and a plurality of groove-shaped oil reservoirs located at a position on the feed-out section side of the oil discharge hole and perpendicular to a path of the yarn wherein cross-sectional areas in the plurality of oil reservoirs have a relationship of S1 ≥ S2 ≥ ··· ≥ Sn,provided that S1 ≠ Sn, where S1, S2, ···, Sn denote the cross-sectional areas of the plurality of oil reservoirs in an order from the one closest to the oil discharge hole to the one remotest from the oil discharge hole; and wherein the first oil reservoir has a larger radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-in section side than a radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-out section side. a feed-in section; a feed-out section; and a middle section located between the feed-in section and the feed-out section and configured to be in contact with a yarn, wherein the middle section includes: an oil discharge hole located at a position on the feed-in section side; and a plurality of groove-shaped oil reservoirs located at a position on the feed-out section side of the oil discharge hole and perpendicular to a path of the yarn wherein cross-sectional areas in the plurality of oil reservoirs have a relationship of S1 ≥ S2 ≥ ··· ≥ Sn,provided that S1 ≠ Sn, where S1, S2, ···, Sn denote the cross-sectional areas of the plurality of oil reservoirs in an order from the one closest to the oil discharge hole to the one remotest from the oil discharge hole; and wherein the first oil reservoir has a larger radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-in section side than a radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-out section side. an oil discharge hole located at a position on the feed-in section side; and a plurality of groove-shaped oil reservoirs located at a position on the feed-out section side of the oil discharge hole and perpendicular to a path of the yarn wherein cross-sectional areas in the plurality of oil reservoirs have a relationship of S1 ≥ S2 ≥ ··· ≥ Sn,provided that S1 ≠ Sn, where S1, S2, ···, Sn denote the cross-sectional areas of the plurality of oil reservoirs in an order from the one closest to the oil discharge hole to the one remotest from the oil discharge hole; and wherein the first oil reservoir has a larger radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-in section side than a radius of curvature of a corner between the yarn-guiding-surface of the middle section and the groove of the first oil reservoir on the feed-out section side.