An electromagnetic wave absorber includes an electromagnetic wave-absorbing layer (10) and an adhesive layer (20). The adhesive layer (20) is disposed on at least one surface of the electromagnetic wave-absorbing layer (10). The electromagnetic wave absorber is capable of being adhered to a surface having a step in such a manner that the adhesive layer (20) is in contact with the surface. The adhesive layer (20) has a thickness equal to or greater than a reference height determined by subtracting 0.1 mm from the height of the step. In the electromagnetic wave absorber, a return loss ΔR defined by ΔR=Rt−Rr is 15 dB or more. Rt is a reflection amount of a 76-GHz electromagnetic wave and is measured for a reference specimen. Rr is a reflection amount of a 76-GHz electromagnetic wave and is measured for a specimen obtained by adhering the electromagnetic wave absorber.