Abstract: The present invention is aimed at providing a waveguide coupling that enables two waveguides to be easily connected together while aligning cross sections of the two waveguides to hold central axes of the two waveguides concentrically with high accuracy. A coupling is for use in connecting two waveguides in an axial direction. The coupling includes a continuous body and a ring member. The continuous body is used to surround in a circumferential direction a connecting portion connecting the two waveguides. The continuous body includes seven partitioning bodies hinged at six portions by gudgeons to become continuous, and the partitioning bodies of end portions are connected together with screws, whereby the continuous body is formed annularly. The ring member has an annular shape, is disposed along a circumference of the waveguide, and is connected to the continuous body by screws.