The present invention provides an optical microscope capable of suppressing unnecessary response light as a background and detecting desired response light in nonlinear optical response process with a good S/N ratio. The optical microscope for collecting, on a sample 8, stimulation light emitted from a stimulation light source 1 and having a single wavelength or a plurality of different wavelengths, and detecting response light emitted from the sample 8 in nonlinear optical response process, comprises: an erase light source 2 for emitting erase light having a wavelength different from that of the stimulation light and inducing an effect of suppressing secondary response light which appears due to irradiation of the stimulation light on the sample 8, wherein the erase light and the stimulation light are simultaneously irradiated on the sample 8 such that the erase light does not suppress response light emitted from a light-collecting area of the stimulation light but suppresses the secondary response light other than the response light emitted from a light-collecting area of the stimulation light.