A circular dichroism spectrometer including: a polarizer configured to transmit light having a specific linear polarization in a light beam coming from a light source; a polarization modulator configured to generate right-handed circularly polarized light and left-handed circularly polarized light alternately by modulating the linearly polarized light; a sample setting portion which is alternately exposed to the right-handed circularly polarized light and the left-handed circularly polarized light; a depolarizer, which is disposed after the sample setting portion to depolarize the beam reflected or transmitted by the sample setting portion; and a detector configured to detect the intensity of the depolarized light, wherein the detector is configured to obtain a difference in absorbance between the right-handed circularly polarized light and the left-handed circularly polarized light in accordance with a change in the detected intensity of light; wherein the depolarizer includes: a pair of wedge-shaped plates (12, 14) made of an optically isotropic material, laid one on top of another such that the total thickness is constant; and wedge-plate holding means for holding the pair of wedge plates (12, 14) separately, wherein each of the pair of wedge plates (12, 14) has the shape of a regular octagon when viewed from the thickness direction, wherein the wedge-plate holding means includes a pressure-applying section (22, 24, 26, 28) for applying pressure to each of the pair of wedge plates (12, 14) in a direction perpendicular to the thickness direction of the pair of wedge plates (12, 14), wherein the pressure-applying direction for one of the pair of wedge plates and the pressure-applying direction for the other of the pair of wedge plates intersect at an angle of 45 degrees. a polarizer configured to transmit light having a specific linear polarization in a light beam coming from a light source; a polarization modulator configured to generate right-handed circularly polarized light and left-handed circularly polarized light alternately by modulating the linearly polarized light; a sample setting portion which is alternately exposed to the right-handed circularly polarized light and the left-handed circularly polarized light; a depolarizer, which is disposed after the sample setting portion to depolarize the beam reflected or transmitted by the sample setting portion; and a detector configured to detect the intensity of the depolarized light, wherein the detector is configured to obtain a difference in absorbance between the right-handed circularly polarized light and the left-handed circularly polarized light in accordance with a change in the detected intensity of light; wherein the depolarizer includes: a pair of wedge-shaped plates (12, 14) made of an optically isotropic material, laid one on top of another such that the total thickness is constant; and wedge-plate holding means for holding the pair of wedge plates (12, 14) separately, wherein each of the pair of wedge plates (12, 14) has the shape of a regular octagon when viewed from the thickness direction, wherein the wedge-plate holding means includes a pressure-applying section (22, 24, 26, 28) for applying pressure to each of the pair of wedge plates (12, 14) in a direction perpendicular to the thickness direction of the pair of wedge plates (12, 14), wherein the pressure-applying direction for one of the pair of wedge plates and the pressure-applying direction for the other of the pair of wedge plates intersect at an angle of 45 degrees. a pair of wedge-shaped plates (12, 14) made of an optically isotropic material, laid one on top of another such that the total thickness is constant; and wedge-plate holding means for holding the pair of wedge plates (12, 14) separately, wherein each of the pair of wedge plates (12, 14) has the shape of a regular octagon when viewed from the thickness direction, wherein the wedge-plate holding means includes a pressure-applying section (22, 24, 26, 28) for applying pressure to each of the pair of wedge plates (12, 14) in a direction perpendicular to the thickness direction of the pair of wedge plates (12, 14), wherein the pressure-applying direction for one of the pair of wedge plates and the pressure-applying direction for the other of the pair of wedge plates intersect at an angle of 45 degrees.