To provide a magnetron for an electronic range, which can make the frequency of microwaves emitted to the outside superior by reducing high-frequency noise caused by a speed difference between electrons transferring through vanes of the magnetron.

The magnetron comprises a positive electrode cylinder, a negative electrode, and a great number of vanes which form a positive electrode part together with the positive electrode cylinder and are each equipped with a first cutoff part 501a housing a large-diameter strip ring and a second cutoff part 501b housing a small-diameter strip ring. An electron-transferring path is installed at a corner of a side surface of the negative electrode in such a manner that electrons can be transferred without interference by the first cutoff part 501a.