An optical measurement device comprising: a light source configured to emit illumination light including a plurality of wavelength components; an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system; a light receiving unit including a spectrometer for separating the reflection light received at the optical system into wavelength components, and a one-dimensional detector including a plurality of light receiving elements arranged one-dimensionally to correspond to the dispersion direction of the spectrometer; a light guide including a plurality of cores optically connecting the optical system and the light receiving unit; a selector configured to selectively supply illumination light from the light source to each of the plurality of cores in the light guide; and a processor configured to compute the distance from the optical system to the measurement object on the basis of a detection value from each of the plurality of light receiving elements in the light receiving unit; the light guide and the light receiving unit being configured so that when a first beam of a first wavelength is provided from the optical system to a first core among the plurality of cores, a light receiving element at which said first beam enters is the same as at least a portion of the light receiving elements at which a second light beam of the first wavelength enters when the second light beam is provided from the optical system to a second core among the plurality of cores; characterised in that the processor is configured to switch the core or cores used to irradiate the measurement object with illumination light in accordance with the shape of the measurement object, to dynamically modify a spot illumination pattern. a light source configured to emit illumination light including a plurality of wavelength components; an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system; a light receiving unit including a spectrometer for separating the reflection light received at the optical system into wavelength components, and a one-dimensional detector including a plurality of light receiving elements arranged one-dimensionally to correspond to the dispersion direction of the spectrometer; a light guide including a plurality of cores optically connecting the optical system and the light receiving unit; a selector configured to selectively supply illumination light from the light source to each of the plurality of cores in the light guide; and a processor configured to compute the distance from the optical system to the measurement object on the basis of a detection value from each of the plurality of light receiving elements in the light receiving unit; the light guide and the light receiving unit being configured so that when a first beam of a first wavelength is provided from the optical system to a first core among the plurality of cores, a light receiving element at which said first beam enters is the same as at least a portion of the light receiving elements at which a second light beam of the first wavelength enters when the second light beam is provided from the optical system to a second core among the plurality of cores; characterised in that the processor is configured to switch the core or cores used to irradiate the measurement object with illumination light in accordance with the shape of the measurement object, to dynamically modify a spot illumination pattern.