A method for cutting a substrate is disclosed which uses a femtosecond laser capable of preventing thermal expansion and generation of shock waves from occurring around a region where a cutting process is carried out when the femtosecond laser is used to cut the substrate, thereby being capable of achieving a reduction in costs. The method includes the steps of arranging the substrate on a stage, and irradiating a femtosecond laser to a predetermined portion of the substrate arranged on the stage, thereby cutting the substrate along the predetermined substrate portion.