A projection-type video image display apparatus measures quantity of light of a plurality of light sources by maintaining illuminance distribution of an illumination luminous flux. The apparatus includes R, B and G light sources, and a mirror configured to reflect white light obtained by synthesizing the light rays emitted from the respective light sources while making the white light pass through the mirror based on predetermined transmittance characteristics. An illuminance sensor disposed on the mirror's back surface and configured to measure quantity of light for each color of the white light which passed through the mirror, and a controller adjusts an amount of light emission of the light source of each color based on the quantity of light measured. The mirror allows the transmittance characteristics of each light transmittance in the center wavelengths of the R and B lights sources to be larger than those of the G light source.