To provide a low-cost wave absorber provided with excellent radio wave absorption characteristics in a wide frequency band and capable of suppressing temperature rise even for irradiation with large power radio waves.

The wave absorber 10 is provided with a structure 11 composed of an assembly of a plurality of cylindrical parts 12. A plurality of the cylindrical parts 12 are respectively formed of a material including a heat resistant base material and a conductive material, provided with an opening part 13 on at least one end side and arranged to be turned to a thickness direction, that is an arriving direction of radio waves 20. On a back surface of the wave absorber 10, a wave reflector 15 such as a metal plate is arranged. The structure 11 is provided with a tapered part 21 having a tapered shape tapered to a surface side and a base part 22 arranged on the opposite side of a radio wave arriving side of the tapered part 21. The opening parts 13 of the respective cylindrical parts 12 are arranged on the surface of the tapered part 21.