To provide an electronic component housing apparatus that is able to efficiently cool the heat of a first and second electronic component, a first electronic component housing chamber 5000 houses the high voltage power supply module 100 (the first electronic component). A second electronic component housing chamber 6000 houses the TWT 200 (the second electronic component). At least some of a first partition plate 2500 and a second partition plate 2600 are provided so as to face each other. A first gap part G1 is provided between the first partition plate 2500 and the second partition plate 2600.