With respect to microwave assisted magnetic recording, high-density information recording is performed by forming a favorable write magnetic domain on a recording medium. The recording medium is placed in a magnetically resonant state by generating a microwave, and information is recorded. A recording medium 7 comprises parts 17 and 18 with differing magnetic anisotropy fields. Recording is performed using, for the frequency of the microwave, a frequency that places the part 17, which has smaller magnetic anisotropy, in a resonant state. Recording density of an information recording apparatus can be increased, while at the same time also improving reliability. Consequently, it becomes possible to reduce costs.