A steam ironing and/or smoothing appliance including an ironing board against which a garment to be ironed can be placed for a steam treatment, the ironing board being mounted with the ability to pivot by a hinge device enabling the ironing board to be immobilized in various tilted positions, the hinge device including a first part which is mobile in rotation in relation to a second part, the first part including at least one notch in which is engaged at least one locking element carried by the second part in order to prevent the hinge device from rotating, wherein the second part is mobile in translation in relation to the first part according to a course and a direction enabling the locking element to engage and disengage in the notch.