A projection apparatus comprising: a light source unit having a plurality of different types of semiconductor light emitting elements (18, 26, 27) with different light emission wavelengths and configured to cyclically output light beams in primary colors and light beams in which the plurality of different types of the semiconductor light emitting elements (18, 26, 27) simultaneously emit light in a time division manner; an input unit configured to input an image signal; an optical image formation unit configured to form an optical image according to the image signal input by the input unit using light emitted by the semiconductor light emitting elements (18, 26, 27); a projection unit configured to project the optical image formed by the optical image formation unit toward a projection target; a plurality of temperature detection units, each being configured to detect, during a color balance correction, a temperature of a respective type of semiconductor light emitting element (18, 26, 27) during a respective primary color light emission; a measurement unit configured to measure, during the color balance correction an intensity of light from each type of the semiconductor light emitting elements (18, 26, 27) during a respective primary color emission using reflected light not being reflected toward the projection unit by the optical image formation unit, wherein the optical image formation unit is further configured, during the color balance correction to form an entirely black optical image during a period in which a single type of semiconductor light emitting elements (18, 26, 27) emits a primary color, and to form an optical image corresponding to a luminance signal according to the image signal input by the input unit during a period in which the plurality of different types of the semiconductor light emitting elements (18, 26, 27) simultaneously emit light; and a light emission control unit configured (a) to correct, during the color balance correction, a measurement result from the measurement unit using a detection result from the temperature detection units by taking into account a temperature-induced wavelength shift of the different types of semiconductor light emitting elements and an associated change in the sensitivity of the measurement unit and (b) to control the light emission intensity for each of the semiconductor light emitting elements (18, 26, 27) based on the corrected measurement result thereby maintaining the color balance among the semiconductor light emitting elements. a light source unit having a plurality of different types of semiconductor light emitting elements (18, 26, 27) with different light emission wavelengths and configured to cyclically output light beams in primary colors and light beams in which the plurality of different types of the semiconductor light emitting elements (18, 26, 27) simultaneously emit light in a time division manner; an input unit configured to input an image signal; an optical image formation unit configured to form an optical image according to the image signal input by the input unit using light emitted by the semiconductor light emitting elements (18, 26, 27); a projection unit configured to project the optical image formed by the optical image formation unit toward a projection target; a plurality of temperature detection units, each being configured to detect, during a color balance correction, a temperature of a respective type of semiconductor light emitting element (18, 26, 27) during a respective primary color light emission; a measurement unit configured to measure, during the color balance correction an intensity of light from each type of the semiconductor light emitting elements (18, 26, 27) during a respective primary color emission using reflected light not being reflected toward the projection unit by the optical image formation unit, wherein the optical image formation unit is further configured, during the color balance correction to form an entirely black optical image during a period in which a single type of semiconductor light emitting elements (18, 26, 27) emits a primary color, and to form an optical image corresponding to a luminance signal according to the image signal input by the input unit during a period in which the plurality of different types of the semiconductor light emitting elements (18, 26, 27) simultaneously emit light; and a light emission control unit configured (a) to correct, during the color balance correction, a measurement result from the measurement unit using a detection result from the temperature detection units by taking into account a temperature-induced wavelength shift of the different types of semiconductor light emitting elements and an associated change in the sensitivity of the measurement unit and (b) to control the light emission intensity for each of the semiconductor light emitting elements (18, 26, 27) based on the corrected measurement result thereby maintaining the color balance among the semiconductor light emitting elements.