An information recording and reproducing method is provided with an information recording method of optically recording digital data onto an information recording medium such as an optical disc etc., by forming a pit having a shape corresponding to the digital data, and an information reproducing method of optically reproducing the recorded digital data from the information recording medium. The information recording method is provided with: a record code generating process of applying an encoding process using a convolutional code onto the digital data, to thereby convert the digital data into a record code; a multi-level symbol generating process of converting the generated record code corresponding to a plurality of bits into a multi-level symbol having a plurality of values; a record symbol generating process of applying a logical converting process onto the generated multi-level symbol to thereby convert the multi-level symbol into a record symbol; and a recording process of recording the record symbol onto the information recording medium by optically forming the pit on the information recording medium while changing the shape of the pit by several steps in correspondence with a value of the generated record symbol. The information reproducing method is provided with: an irradiating process of irradiating a light beam for reproducing the digital data so that an irradiation range of the light beam on the information recording medium covers a plurality of pits.