It is aimed to suppress a local increase of an energy density per unit time in a nonlinear crystal. A fundamental wave emitted from a fundamental wave laser light source is condensed by a condenser lens and incident on a nonlinear crystal 11 having a poled structure. By displacing a focus position of a fundamental wave 50 by means of a scanning mirror 21, a local increase of the energy density per unit time in the nonlinear crystal 11 is suppressed.