The present invention proposes a heater assembly which is able to effectively heat water in a water tank. The heater assembly comprises: an inner bowl (2) which receives a positive pole; and outer bowls (4) installed on an outer side of the inner bowl at regular intervals, which have a vertical passage (20). In addition, the heater assembly is supported on a side surface of the water tank by using a mounting plate (30) having a hanging bump which can hang on the outer side toward a mounting hole on a side wall of the water tank. In addition, a first supporter (42a) electrically connects a positive pole contact point unit formed on an outer side of the mounting plate (30) to the inner bowl. A second supporter electrically connects a negative pole contact point unit formed on an outer side of the mounting plate (30) to the outer bowl. The water introduced through a passage (20) of the outer bowl is heated between the inner bowl (2) and the outer bowl (4), and flows to the outside through an upper side of the passage (20). COPYRIGHT KIPO 2022