To avoid deterioration of isolation between two distributed power outputs in higher and lower end portions of an available frequency region of a Wilkinson power distributor, plural stages of ferrite-loaded close-coupled parallel dual lines for providing a Wilkinson power distributor, an electric length of which lines is shortened within a range in which desired isolation can be obtained, are connected in cascade. As a result, two distributed power outputs having a constant phase difference with sufficient isolation throughout an extremely wide frequency range can be obtained.