Abstract: A light source device includes a light source having a light emitting element, a thermal conductor, an optical system housing, and a cooler. The thermal conductor has a first surface and a second surface, and the light source is thermally connected to the first surface. The optical system housing has a mounting part with an opening. The thermal conductor is fixed to the optical system housing in a state that the first surface is disposed in a direction facing the mounting part and the light emitting element is disposed at a position facing the opening. The cooler is thermally connected to the second surface of the thermal conductor and cools heat from the light source.

Abstract: A projection image display device 1 includes a housing 100, a projection lens 110, a front convex portion 50A and a rear convex portion 50B. The housing 100 accommodates an illumination optical system and a modulation optical system in an interior thereof. The projection lens 110 is configured to project an image modulated by the modulation optical system in a scaled-up size, and is disposed on a first lateral face 100b of the housing 100. The front convex portion 50A and the rear convex portion 50B are disposed on an intersection line between a plane containing an optical axis of the projection lens 110 and a top face 110a of the housing 100.