Abstract: A molecular structure analysis device of at least one embodiment of the present invention includes: a light source for illuminating, with exciting light, a measurement sample including a molecule to be structurally analyzed to which molecule a rare earth complex is bonded; a measurement section for receiving light emitted from the measurement sample and for measuring intensities of spectra of the light; a calculation section for performing normalization in which intensities of spectra including a line spectrum due to electric dipole transition among the measured intensities of the spectra of the light are normalized by an intensity at one wavelength in a line spectrum due to magnetic dipole transition; and an output section for outputting the spectra whose intensities have been normalized. This makes it possible to attain a device and a method capable of analyzing minute change in a dynamic structure of the molecule.