(1) A two-photon absorbing polymerization method comprising a first step of irradiating light absorbable by two-photon absorption to form a latent image and a second step of exciting the latent image to cause polymerization, and (2) A two-photon absorbing optical recording method comprising a first step of forming a latent image of a color-forming material by two-photon absorption, a second step of irradiating light on the latent image of a color-forming material to cause polymerization based on the linear absorption of the color-forming material, and thereby forming difference in the refractive index to perform a recording, are provided.