To provide a hair iron which can make hair wavy in a single movement and close with an openable heating part directly held by the hand.

The hair iron is structured as follows: a pair of freely openable heating parts are held by the hand to be closed; a pair of the heating parts includes a right-and-left-protruding and center-recessed heating part 10 having a heating surface formed by making the inside ends of the right and the left of the pair of protruding semi-circular heating surfaces 10B, 10B continue to both ends of a center-recessed semi-circular heating surface 10A to be waved, and a right-and-left-recessed and center-protruding heating part 20 having a heating surface formed by making the inside ends of the right and the left of the pair of recessed semi-circular heating surfaces 20B, 20B continue to both ends of a center-protruding semi-circular heating surface 20A to be waved; thick parts 11, 11 are formed on the back surface of the right and the left of the pair of protruding semi-circular heating surfaces 10B, 10B of the right-and-left-protruding and center-recessed heating part 10; and also a thick part 21 is formed on the back surface of the center-protruding semi-circular heating surface 20A of the right-and-left-recessed and center-protruding heating part 20.