An illumination device includes an optical fiber holder configured to hold an optical fiber, a phosphor holder configured to hold a phosphor and faces the optical fiber holder, and a bonding material configured to intervene between the optical fiber holder and the phosphor holder to bond them. The illumination device includes adjustment guide members configured to intervene between the optical fiber holder and the phosphor holder, relatively positionally adjust the optical fiber holder and the phosphor holder so as to arrange an optical axis of the optical fiber and an optical axis of the phosphor on one line, and configured to prevent the optical fiber holder and the phosphor holder from tilting when the bonding material is cured.