A pumping module is provided with a first square rod group including a first square rod having two heat sinking surfaces normal to a direction of y axis perpendicular to an optical axis, and a second square rod having two heat sinking surfaces normal to a direction of x axis perpendicular to the optical axis and the direction of the y axis, and a second square rod group including a third square rod having two heat sinking surfaces normal to the direction of the y axis and a fourth square rod having two heat sinking surfaces normal to the direction of the x axis. A polarization rotator is disposed between the first and second square rod groups, for rotating a polarization of laser light passing therethrough by 90 degrees.