A method for manufacturing an optical disk master includes: forming a resist layer by the application of a chemically amplified resist; converting an information signal into a multipulse signal having a symmetrical shape; exposing the resist layer in accordance with the multipulse signal; heat-treating the resist layer; and developing the resist layer to form signal pits. The signal pits are exposed to the multipulse signal, which is obtained by dividing a pulse into symmetrical pulses, thereby adjusting the exposure area and achieving a desired pit shape.