A device for measurement of the spectral reflectance of a surface where the reflectance factor of light with a certain wavelength can be measured in a wide wavelength range, including the UV range, and in which a reference reflectance factor can be easily obtained. The device for measurement has a light source part with a xenon lamp; a fiber on the incidence side; a measurement head which emits the light transmitted by the fiber via a convergent lens and a diffuser onto the surface of the measuring object and which receives the light reflected by the surface; a fiber on the exit side; and a spectroradiometer which receives the light which has been transmitted by the fiber on the exit side.