The invention discloses a novel instant constant-temperature electric water heater. The novel instant constant-temperature electric water heater comprises an electric control module, a water heating module, a water inlet flow adjusting module and a water pressure difference safety control module; the water heating module comprises a cylindrical membrane type heater, a water inlet electricity insulation wall and a water outlet electricity insulation wall, the water inlet electricity insulation wall and the water outlet electricity insulation wall are arranged in a water channel of the membrane type heater, a spiral water channel is arranged on the outer wall of the water channel, a metal pipe is arranged outside the spiral water channel in a sleeving mode, and a membrane type heating circuit is arranged on a wall of the metal pipe in a laid mode; and the water pressure difference safety control module comprises a first plastic base, a water channel in the plastic base and a differential pressure switch, the differential pressure switch is installed on the plastic base, and a high pressure bin and a low pressure bin of the differential pressure switch communicate with a water inlet channel and a middle water channel in the plastic base respectively. The novel instant constant-temperature electric water heater can effectively solve the problems that occupied space of the electricity insulation walls is large and the electricity insulation effect is not ideal and has the advantages of being ingenious in structure, convenient to use, safe and reliable.