The back kneading device mounted in the chair-type massage apparatus comprises: the massage mechanism including paired right-hand and left-hand massage members having the treatment element for massage and the driving section for transmitting massage action to the massage member; the base member for supporting the massage mechanism, with the massage member pointing forward; the vertical movement mechanism for moving the base member in the vertical direction in the backrest; and the protruding-amount varying mechanism for moving the massage member so that protrusion amount of the treatment element in the front-rear direction can be varied.