A color wheel device is used in a projector. The color wheel device includes a housing, a color wheel, a motor, and a thermally conductive member. The housing has at least one through hole for a light beam to pass through. The color wheel is disposed in the housing and includes a substrate and a phosphor layer. The substrate has a light-receiving surface. The phosphor layer is disposed on the light-receiving surface. The light beam forms a light spot on the phosphor layer. The motor is disposed in the housing for driving the substrate to rotate. During the rotation of the substrate, the light spot forms a circular path on the phosphor layer. The thermally conductive member is disposed on the housing substantially at a location to which the circular path maps.