Provided is a humidification and air cleaning apparatus. The humidification and air cleaning apparatus includes: a base body including a water tank insertion space formed therein; a water tank having an upper side thereof opened, storing water therein, placed in the water tank insertion space, and separable from the base body; a top cover assembly disposed over an opened upper part of the water tank and disposed separably from the water tank; an air wash inlet formed at a side of the water tank and receiving air into the water tank; a discharge flow passage formed in at least one of the top cover assembly and the water tank, or formed between the top cover assembly and the water tank; and a water supply flow passage disposed inside the top cover assembly and guiding water into the water tank.