An electron tube of the present invention includes: a vacuum vessel including a face plate portion and a stem portion arranged facing the face plate portion; a photocathode arranged in the vacuum vessel and formed on the face plate portion; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the face plate portion, and made of an insulating material; an electron detector arranged on the projection portion, made of a semiconductor, and having a first conductivity-type region and a second conductivity-type region; and a first conductive film covering a surface of the projection portion and to be electrically connected to the first conductivity-type region.