Numerical and experimental analyses revealed the enhancement of diffusion of oxygen and boron by laser irradiation. We studied the effect of laser irradiation on the enhancement of diffusion of boron and oxygen including both isotopes of 16O and 18O. The study clarified that the diffusion of the impurities was enhanced by laser irradiation by about 2.5-8 times more than that in the case without laser irradiation in the temperature range from 990 to 1200℃. We confirmed from temperature measurements of the samples that such enhancement was not based on temperature increase caused by laser irradiation but was based on the effect of irradiation of the laser. The effect of frequency of the laser on the diffusion was observed by changing the wavelength of the laser.