An up-conversion laser unit in which a semiconductor laser of high output power can be used as a pump light source and the wavelength of up-converted laser light is suitable for display. The light of infrared wavelength is generated by the pump light source, the generated light being inputted into a Pr3+ up-conversion laser to up-convert there into red light by Pr3+ ion. The up-converted red light is inputted into, as a pump light source, a Tm3+ up-conversion laser, there being up-converted into blue light by the Tm3+ ion. Thereby, efficient up-conversion into blue light is made possible.