A substrate housing portion stores a circuit substrate that outputs an image signal. The optical unit generates and projects an image based on the image signal output from the circuit substrate. The image is projected onto a combiner. The optical unit has an optical unit main body that includes a light source and an image display element, and a projection unit that is attached to the optical unit main body and that determines a projection direction. The projection unit is provided with an intermediate image screen that images an intermediate image and is freely removed from or installed in the optical unit main body.