A balanced-type circular disk resonator includes a circular conductive layer, a conductive member including a first conductive portion provided on a first surface of the circular conductive layer to enable a first dielectric board, a dielectric property of which is measured, to be placed between the first conductive portion and the circular conductive layer, and a second conductive portion provided on a second surface of the circular conductive layer to enable a second dielectric board, a dielectric property of which is measured, to be placed between the second conductive portion and the circular conductive layer, the second surface being opposite to the first surface with regard to the circular conductive layer, and a temperature adjustment unit coupled to the conductive member and configured to adjust temperatures of the first conductive portion and the second conductive portion.