MAGNETRON

PURPOSE:To make alignment possible in assembling a magnetron without using any specific alignment part, prevent falling of the gasket and coming out of alignment due to a shock, by providing the exterior seal part on the output side with a drawn portion having openings such as slits or holes provided therein. CONSTITUTION:The seal part 6 is provided in the center thereof with an opening 6a of vertually equal size to the seal portion on the outside 1a of the magnetron main body 1, and on the circumferential portion thereof with two pairs of drawn portions 6b projecting in the axial direction and facing each other and two pairs of openings, or slits 6c, disposed in the lateral directions, the drawn portions 6b and the slits 6c being disposed one after the other at equal pitches. A gasket 7 is inserted in the seal part in such a manner that portions of the gasket are retained being engaged with the slit portions 6c between two drawn portions 6b. By virtue of such a seal part, the alignment in the assembling of the magnetron is made easy and accurate, the gasket is prevented from falling off, and a reliable magnetron can thus be provided.