The invention discloses a convenient and safe electric can opener with automatic control and simple structure. The electric can opener comprises a bottom cover (1), a face cover (3), a power supply, a motor (4), a blade (14), a rotating wheel (10), a transmission device (25), a switch (20), a hand wheel (91), a safety protective switch and an automatic controlling device. The automatic controlling device comprises a transmission gear (9), an eccentric wheel (12), a transmission part (16) and a control switch (41). The electric can opener is controlled by the automatic controlling device for automatically completing the process of extending the blade, cutting and retracting the blade. The electric can opener can be widely used for opening various iron cans.