A novel two way rotary junctor is presented. One way of the rotarv junctor is designed at S band, and another way is designed at P band. The VSWR for S band rotary junctor is less than 1.2 in the 1.2-4.4 GHz frequency range. A reentrant resonant cavity is used for the design of the P band roiary junctor in order to reduce the length of the rotary junctor. The total length of two way rotary junctor is /4 approximately. It satisfies the needs for the especially small size.