To provide an electron-beam tube and a window for electron beam extraction capable of preventing failure due to heat and of raising the power of the electron beam by effectively releasing heat generated by electron beam passing the window outside the window and suppressing the temperature rise of the window.

In the window 5 of the electron-beam tube provided with an electron beam generator inside a vacuum vessel in which a window 5 emitting an electron beam is formed, first projections 52 continuously provided on one surface of the window 5, and second projections 53 positioning corrsponding to a region 51 formed between the first projections 52 and continuously provided on one or the other surface of the window 5 having smaller projection height, projection width and distance between the second porojections 53 than those of the first projection are formed.