To enable agitating the contents in a container well simultaneously with heating them by rotating a turntable driving head at a first rotation speed and also rotating an agitating blade in the container at a second rotation speed larger than the first rotation speed at the operation of a microwave oven.

A magnetic agitating device 10 used in a microwave oven 5 having a turntable driving head 7 has a base member 12, an upper support member 14, and a gear line assembly 16 inserted between both the members 12, 14. The gear line assembly 16 has a driving head coupler 18 connected to the driving end part thereof, and to the driven end part thereof, an agitating actuator 20 is connected. When power is transmitted to the driving head coupler 18, a container 94 mounted on a platform 90 is turned in the oven 5. And on this turning, an agitating bar 228 in the container 94 is rotated through magnetic coupling with the actuator 20 at the same time, thereby performing agitation of the contents.