A wall mounted washing machine and its door opening and closing device are provided to maximize the user's convenience in opening and closing a door. The wall mounted washing machine includes a tub disposed in a cabinet to store wash water; a front panel installed in the tub; a cover installed in the front panel and provided with a door hinge;;a door rotatably coupled to the door hinge; and a door opening and closing device to lock and unlock the door and the cover. The door opening and closing device includes: a door hanging unit provided on the door and protruding toward the cover; a door locking unit provided on the cover to lock the door hanging unit and release the locking of the door hanging unit through the operation by a door opening button by means of an electronic opening and closing method.
