An optical microscope comprising: a light source configured to generate a light beam; a first scanner configured to deflect the light beam and scan a spot position of the light beam on a sample; an objective lens configured to focus the light beam deflected by the first scanner and cause the light beam to be made incident on the sample; a spectroscope including a slit on an incident side which an outgoing light emitted from an area on the sample onto which the light beam has been illuminated enters; a two-dimensional array photodetector including light-receiving pixels arranged in an array, the two-dimensional array photodetector detecting an outgoing light from the spectroscope; and a first relay optical system including a first off-axis parabolic mirror and a second off-axis parabolic mirror, the first off-axis parabolic mirror being arranged in an optical path from the first scanner to the objective lens and reflecting the light beam deflected by the first scanner, and the second off-axis parabolic mirror reflecting the light beam reflected in the first off-axis parabolic mirror, wherein the first off-axis parabolic mirror and the second off-axis parabolic mirror are concave mirrors having paraboloids, geometric symmetry axes of the first and second off-axis parabolic mirrors are parallel to each other and the paraboloids face in directions opposite to each other, a second direction corresponds to a longitudinal direction of the slit in a plane perpendicular to a reference axis of the light beam between the first and the second off-axis parabolic mirrors is within a plane including the geometric symmetry axes, the reference axis of the light beam between the first and the second off-axis parabolic mirrors is a line that the light that enters a pupil of the objective lens at an incident angle of 0 degrees or a principal ray of the outgoing light emitted at 0 degrees from the pupil of the objective lens passes. a light source configured to generate a light beam; a first scanner configured to deflect the light beam and scan a spot position of the light beam on a sample; an objective lens configured to focus the light beam deflected by the first scanner and cause the light beam to be made incident on the sample; a spectroscope including a slit on an incident side which an outgoing light emitted from an area on the sample onto which the light beam has been illuminated enters; a two-dimensional array photodetector including light-receiving pixels arranged in an array, the two-dimensional array photodetector detecting an outgoing light from the spectroscope; and a first relay optical system including a first off-axis parabolic mirror and a second off-axis parabolic mirror, the first off-axis parabolic mirror being arranged in an optical path from the first scanner to the objective lens and reflecting the light beam deflected by the first scanner, and the second off-axis parabolic mirror reflecting the light beam reflected in the first off-axis parabolic mirror, wherein the first off-axis parabolic mirror and the second off-axis parabolic mirror are concave mirrors having paraboloids, geometric symmetry axes of the first and second off-axis parabolic mirrors are parallel to each other and the paraboloids face in directions opposite to each other, a second direction corresponds to a longitudinal direction of the slit in a plane perpendicular to a reference axis of the light beam between the first and the second off-axis parabolic mirrors is within a plane including the geometric symmetry axes, the reference axis of the light beam between the first and the second off-axis parabolic mirrors is a line that the light that enters a pupil of the objective lens at an incident angle of 0 degrees or a principal ray of the outgoing light emitted at 0 degrees from the pupil of the objective lens passes.