We investigated the antiferromagnetic-ferromagnetic phase transition of FeRh nanowires induced by an electric current. The critical current I-cr for the phase transition decreases with increasing the sample temperature. It is found that the RcrIcr2, where R-cr is the resistance at I-cr, linearly decreases as the sample temperature increases, suggesting that the temperature raised by the Joule heating is responsible for the transition. We also studied for various wire widths to characterize the heat dissipation of the nanowires. Our results provide a way to explore the Joule heating in high density nanosized electrical devices where significant electric current flow is involved. (C) 2015 The Japan Society of Applied Physics