Provided is a laser processing method for drilling a hole in a glass substrate with using a carbon dioxide laser, including the steps of: irradiating the laser onto a drilling position on the glass substrate from a side of the glass substrate on which a protective sheet is adhered so as to form a blind hole; removing the protective sheet from the glass substrate and performing an annealing treatment; and performing a wet-etching process on a side of the glass substrate not irradiated with the laser so as to convert the blind hole into a through hole.