Head-up display apparatus

A head-up display apparatus, comprising:

• a display unit configured to output projection light;
• at least one reflector configured to reflect the projection light;
• a housing, which has an opening portion, and is configured to store the display unit and the reflector therein;
• a cover member configured to cover the opening portion;
• and
• a polarizing plate with a retardation layer, which is arranged on a housing inner side of the cover member, and includes a retardation layer and a polarizer in the stated order from a cover member side,
• wherein the retardation layer has an in-plane retardation Re(550) of 3,000 nm or more,
• wherein the head-up display apparatus is configured so that an angle of reflection of the projection light output from the housing through the opening portion with respect to a windshield is from 2° to 35°, is from 40° to 45°, or is from 75° to 89°,
• wherein the angle of reflection and an angle of incidence of the projection light have the same value, and
• wherein an angle formed between an absorption axis of the polarizer and a slow axis of the retardation layer is from 35° to 55°.