An electronic device comprising: a first reflective film that is arranged to transmit a portion of incident light and reflects a portion thereof; a second reflective film, disposed so as to face the first reflective film, which is arranged to reflect a portion of incident light and transmit a portion thereof; a gap control unit that is arranged to change a size of a gap between the first reflective film and the second reflective film; and a gap change portion that is arranged to change the size of the gap by applying a voltage; wherein the gap control unit is arranged to control the size of the gap corresponding to a wavelength to be measured, on the basis of an order of a transmission spectrum which is set with respect to each of two or more wavelength regions constituting a wavelength region to be measured, wherein the wavelength region to be measured includes a first wavelength region and a second wavelength region having a longer wavelength than that of the first wavelength region, the first wavelength region being the region of lowest wavelengths in the wavelength region to be measured, characterized in that: the gap control unit includes a storage unit that stores V-λ and order data, in which a voltage applied to the gap change portion with respect to a wavelength to be measured is recorded for one or more orders of each wavelength to be measured, and wherein only one order is set in advance with respect to each wavelength to be measured, such that the gap control unit applies the voltage corresponding to the order set in advance for each wavelength to be measured, and wherein the order which is set with respect to the wavelength to be measured belonging to the first wavelength region is higher than the order which is set with respect to the wavelength to be measured belonging to the second wavelength region, and wherein the electronic device further comprises a processing control unit and a detection unit, the detection unit comprising a single detector that is arranged to detect the light extracted by the first reflective film and the second reflective film, and the processing control unit being arranged to cause a transformation matrix for transforming a measurement spectrum into an optical spectrum to act on the measurement spectrum based on the amount of light of each wavelength to be measured which is detected by the detection unit, and estimate an optical spectrum of measurement light incident on the first reflective film and the second reflective film. a first reflective film that is arranged to transmit a portion of incident light and reflects a portion thereof; a second reflective film, disposed so as to face the first reflective film, which is arranged to reflect a portion of incident light and transmit a portion thereof; a gap control unit that is arranged to change a size of a gap between the first reflective film and the second reflective film; and a gap change portion that is arranged to change the size of the gap by applying a voltage; wherein the gap control unit is arranged to control the size of the gap corresponding to a wavelength to be measured, on the basis of an order of a transmission spectrum which is set with respect to each of two or more wavelength regions constituting a wavelength region to be measured, wherein the wavelength region to be measured includes a first wavelength region and a second wavelength region having a longer wavelength than that of the first wavelength region, the first wavelength region being the region of lowest wavelengths in the wavelength region to be measured, characterized in that: the gap control unit includes a storage unit that stores V-λ and order data, in which a voltage applied to the gap change portion with respect to a wavelength to be measured is recorded for one or more orders of each wavelength to be measured, and wherein only one order is set in advance with respect to each wavelength to be measured, such that the gap control unit applies the voltage corresponding to the order set in advance for each wavelength to be measured, and wherein the order which is set with respect to the wavelength to be measured belonging to the first wavelength region is higher than the order which is set with respect to the wavelength to be measured belonging to the second wavelength region, the gap control unit includes a storage unit that stores V-λ and order data, in which a voltage applied to the gap change portion with respect to a wavelength to be measured is recorded for one or more orders of each wavelength to be measured, and wherein only one order is set in advance with respect to each wavelength to be measured, such that the gap control unit applies the voltage corresponding to the order set in advance for each wavelength to be measured, and wherein the order which is set with respect to the wavelength to be measured belonging to the first wavelength region is higher than the order which is set with respect to the wavelength to be measured belonging to the second wavelength region, and wherein the electronic device further comprises a processing control unit and a detection unit, the detection unit comprising a single detector that is arranged to detect the light extracted by the first reflective film and the second reflective film, and the processing control unit being arranged to cause a transformation matrix for transforming a measurement spectrum into an optical spectrum to act on the measurement spectrum based on the amount of light of each wavelength to be measured which is detected by the detection unit, and estimate an optical spectrum of measurement light incident on the first reflective film and the second reflective film.