Abstract: The invention relates to a device for treating the hair, comprising a first (5) and a second 86) arm that are able to move relative to one another between a moved-together configuration for treating the hair and a spaced-apart configuration for inserting hair to be treated between said arms, the first arm carrying an applicator member (26) for applying a cosmetic product that is able to come into contact with the hair in the moved-together configuration of the arms, and the second arm having at least one housing (38); a pressing element (21) disposed removably in the housing, the pressing element being configured to press the hair against the applicator member in the moved-together configuration; and a support means (40) on which the pressing member bears in the housing, this support means being configured to allow the pressing element to carry out a rocking movement in the housing.