An isotope exchange technique is employed as a method for measuring the nitrogen dissolution rate into molten iron alloys, and the effects of Al, Si, and B addition have been studied at temperatures ranging from 1873 to 2023 K. The results are compared with those of other elements such as Ti, Zr, V, and Cr. The rate of nitrogen dissolution into molten iron is shown to decrease by the addition of Al, Si, and B due to a weaker affinity for nitrogen than Fe, which is contrary to the case of Ti, Zr, V, and Cr. Among them, B shows the largest effect when their contents are lower than 1 mass pct. A reasonable correlation of the rate constant with an interaction parameter between nitrogen and each element has been observed, which can be explained by the change in the activity of the vacant site on the surface of the molten alloy.