A hair treatment device includes a first and a second arm, movable in relation to each other, which can be opened to introduce a strand of hair between them and closed to treat the strand of hair, a first and second contact surfaces respectively supported by the first and second arms, arranged facing each other, with at least one of the contact surfaces being heated, at least the first arm having at least one first piece supporting the first contact surface, a sealing element including a central window arranged such that it extends at least partially around the first contact surface between the latter and the first supporting piece, wherein the sealing element includes at least one opening that is distinct from the central window and the first supporting piece and the first contact surface come into contact with each other through the at least one opening.