A laser processing method including a first step of irradiating a surface of a workpiece with a laser beam with a focal point spaced from the surface, and forming a bottomed hole on the workpiece, which is defined with a tubular inner circumferential face opening at the surface and a bottom face; and a second step of irradiating the bottom face with a laser beam while an assist gas is blown into an opening of the bottomed hole but not blown onto an area surrounding the opening, and forming a through hole penetrating through the workpiece. A laser processing system includes a processing head focusing a laser beam emitted from a laser oscillator so as to irradiate a workpiece with the laser beam and blowing an assist gas onto the workpiece; and a control section controlling the first and second steps as an operation of the processing head.