An optical recording-reproducing method comprising the step of irradiating a radiation for polymerization on an optical recording medium having a recording layer containing at least one selected from the group consisting of azulenium salt compounds, pyrylium dyes, diene compounds, croconic methine dyes and polymethine compounds (hereinafter called the group B) and a diacetylene derivative compound; the step of irradiating a radiation corresponding to a recording information to thereby change the color at the irradiated portion of the recording layer; and the step of reading the recorded information by irradiating a reading light with a shorter wavelength than said radiation on said recording layer. Also, an optical recording-reproducing device utilizes the above-mentioned method.