WAVEGUIDE TYPE FILTER

PROBLEM TO BE SOLVED: To obtain a waveguide type filter which has an improved adjustment mechanism that easily and also stably adjust electrical characteristics by allowing a 1st cavity part to be in a short circuit state at its starting end and allowing a 2nd cavity part making the terminating end of the 1st cavity part a starting end to be in an open state at its starting end. SOLUTION: The starting end of a 1st cavity part 3 is an inner wall surface X0, and the length up to its terminating end is l1. The terminating end of the 1st cavity part 3 is also the starting end of a 2nd cavity part 4 in the direction of the screw axis, and the length up to the terminating end in the screw axial direction of the 2nd cavity part 4 is l1. Then, an impedance obtained by seeing a screw 51 side from the X0 point is in an almost short-circuited state, and an impedance obtained by seeing an X2 point side from an X1 point. Because of this, electromagnetic waves in a resonator are made different to enter into the screw 51 side, and the effect of a contact failure in the neighborhood of the root of the screw 51 is also eliminated. Then, the adjustment of an electrical characteristic becomes easier than in a conventional type adjustment mechanism.