Abstract: A head-up display is applied for a moving body that includes a windshield, an air-conditioning unit having a blow-out opening, and a blow-out outlet. The head-up display includes a light source that emits display light and an optical path housing that defines therein an optical path for the display light. The display light reaches the windshield and the information is displayed on the windshield. The head-up display further includes an air-conditioning duct that defines an air flow path. The light source is exposed to the air flow path and radiates heat in the air flow path. The optical path housing and the air-conditioning duct commonly includes a separation wall that separates the air flow path and the optical path.