An illumination device including a light-emitting tube having a light-emitting member in which light emission is carried out between a pair of electrodes and sealing members located on both sides of the light-emitting member, a first reflecting mirror to hold the light-emitting tube, reflect the light emitted from the light-emitting tube, and direct the light forward, and a transparent plate disposed in a distal end portion of the first reflecting mirror, a second reflecting mirror that encloses a front portion of the light-emitting member and reflects the light from the light-emitting member toward the first reflecting mirror being fixed to at least one of the sealing member and the transparent plate, the transparent plate and the second reflecting mirror are brought into contact or fixedly attached to each other, and at least one of the transparent plate and the second reflecting mirror is brought into contact or fixedly attached to the sealing member.