A soldering iron including an iron main body and an iron tip includes an iron tip main body having a hollow space inside extending along a longitudinal direction; an insulator tube in the hollow space; a heater wire to heat the iron tip main body, and a temperature sensor to detect a temperature of the leading end side of the iron tip, the heater wire includes: an outward route part extending towards a leading end of the iron tip, and a return route part extending towards a base end of the iron tip, while the heater wire folded back at a vicinity of the leading end of the iron tip being wound around the insulator tube, in the insulator tube, a heater wire hole to accommodate the return route part of the heater wire and a sensor wire hole to accommodate a sensor wire are formed independent of each other.