1. An information recording method, comprising the steps of: at a time of recording information, recording information to semiconductor memory in a case where an amount of free space in a recording area of the semiconductor memory equals or exceeds a first predetermined range; recording information to magnetic memory in a case where the amount of free space in the recording area of the semiconductor memory is less than the predetermined range, and wherein an amount of free space in the recording area of the magnetic memory equals or exceeds a second predetermined range; recording information to optical memory in a case where the amount of free space in the recording areas of both the semiconductor memory and the magnetic memory are less than a third predetermined range; and at a time of retrieving recorded information, incrementing an access count, and moving information with a comparatively high access count to the semiconductor memory, while moving information with a comparatively low access count to the optical memory.