The present invention relates to an optical amplification module having a construction which effectively suppresses photodarkening, and to a laser light source including the same. The laser light source comprises a light source for outputting light to be amplified, and an optical amplification module. The optical amplification module comprises two types of optical amplification media having different rare earth element concentrations, and a pumping light source. The low concentration medium and the high concentration medium are disposed in the propagation direction of pumping light such that the population inversion of the low concentration medium is higher than that of the high concentration medium. Hence, by arranging two types of optical amplification media with different rare earth concentrations such that the population inversion of the low concentration medium is higher than that of the high concentration medium, sufficient overall gain of the laser light source can be obtained while effectively suppressing photodarkening in the two types of optical amplification media.