When condensation occurs in a blade passage in a steam turbine, it affects an oblique shock wave originating from the trailing of the blade. In the present study, a condensing flow was produced by an expansion of moist air in a supersonic circular nozzle, and, by inserting a wedge-type shock generator placed in the supersonic parts of the nozzle, the effects of condensation on an oblique shock wave were investigated experimentally. As the result, the position of the oblique shock wave relative to the condensation zone and the change of shape of the oblique shock wave due to condensation are discussed. Furthermore, the load working on the nozzle wall, obtained from the measurement of pressure distribution, and the effect of condensation on the load are discussed.