PURPOSE: To obtain a resistive terminator withstanding a large power by arranging an electromagnetic wave absorbing body in a rectangular coaxial line at a position parted from its center conductor so as to attain a required quantity of absorbing amount thereby uniforming the temperature distribution of the absorbing body in a guide axis direction.

CONSTITUTION: The size of the center conductor 4 and the outer conductor 6 is decided in general so that its electric impedance is 50 ohms. In order to decrease the impedance change when the electromagnetic wave absorbing body 5 is mounted, the relation of distance X>> distance Y is established. Further, one end of the center conductor 4 is fixed to the center conductor of a coaxial line input terminal 3 and one end is fixed to the outer conductor 2. The electromagnetic wave absorbing body 5 is arranged at a position parted from the center conductor 4 by a distance (l) and fixed to the outer conductor 2 to attain excellent thermal conduction. Further, the distance is decided to be l1>l2>l3>l4, and the distance (l) is an important factor deciding the electromagnetic wave absorbing quantity of the electromagnetic wave absorbing body and uniforming the generated heat energy and decided experimentally.