The invention belongs to the field of electric heaters and in particular to an instantaneous
water heater using an
electric heating film tube. The heater comprises a controller (1), a backwater chamber (7), a heater
assembly (23) and a heater body, wherein the controller (1) is composed of a hexagonal hollow rotary
handle (3), a sealing ring A (2), a baffle ring (4), a press cap (5), a press spring (8), a sealing ring B (11), an arc contact blade (12), an indicator light (13), a contact (4) in the shape of a Chinese character 'ding'; the backwater chamber (7) is composed of an
alcove integrated with the hexagonal hollow rotary
handle (3) and a water selecting plate (9); the heater
assembly (23) is composed of a combined sleeve A (10), a
hollow cylinder (15), a baffle board (160), a wiring frame (17), the
electric heating film
pipe (18), a heating
pipe frame (19), a reed
pipe (20), a
junction box (21) and a combined sleeve B (22); and the heater body is composed of an upper heater body (6), a lower heater body (24), a power plug (25), a cool water inlet pipe (26) and a mounting nut (27). The heater is characterized in that the controller (1) has the functions of dispersing water and controlling water, and switching on and off the
electricity, and when the controller (1) is rotated, the hot water or cool water is selected at random; and the heater
assembly (23) has the characteristic of efficiently and rapidly outputting hot water with high flow.