The device is designed to open or close a door of a microwave oven more smoothly. The device includes : a door opening/closing switch (2) for a door (1); a door opening/closing switch restoration spring (3); a door opening/closing switch groove (4); a door opening/closing switch lever (5); an interlocking plate (7) engaged with an interlocker (6); an interlocking support stand (8); a door hook guide plate (11) for supporting a door hook (9); a door hinge (13); a door spring (14); a sun gear (15); and a planetary gear (16).
