Provided are an optical module and an image display apparatus, in which an adjustment position of a compensation plate is easily maintained even in a case where the image display apparatus is miniaturized, and a method of manufacturing the image display apparatus. An optical module including a fixing part that fixes an adjustment position of a phase difference compensation plate in a Z-axis direction perpendicular to a main surface of a liquid crystal panel; a projection type image display apparatus including a light source, a rotation body that rotationally adjusts, by an angle adjustment member, rotation of a phase difference compensation plate disposed between a liquid crystal panel and a polarized beam splitter of the liquid crystal panel, and a holder part that fixes the angle adjustment member of the rotation body to a fixing part in a Z-axis direction; and a method of manufacturing an optical module, the method including fixing an adjustment position of a phase difference compensation plate in a Z-axis direction perpendicular to a main surface of a liquid crystal panel.