Condensation phenomena in the injection of the emergency coolant water to the core is an important topic to be verified by a number of realizing experiments. Many experimental studies, however, have been conducted in square type test section in which the steam flow forms two-dimensional flow because there was not an effective measurement technique of local steam flow rates used to estimate the condensation rates in circular pipes, To develop an effective LDV measurement technique of local steam flow rates in circular pipes, some experimental tests in a circular pipe, which is 70 mm in diameter, and analyses for the method of data handling were conducted. The spatial distributions of steam velocity are obtained from the tests for with-water case and no-water case and they are fitted to a 1/7 power curves which is widely known as a distribution of steam velocity in circular pipes. The distributions show good agreement with the fitting curves. The stability of LDV signal is tested by an experiment in which the velocities of liquid droplets at a point are measured 20 times repetitively. It is found from the test that the fluctuations between LDV signals during the 20 times measurement are relatively large, In the present work, therefore the maximum value among the 20 data is selected as a representative data at the point. For a practical application of LDV technique, a method for selecting the measurement points among the total measuring points is proposed. With the further studies for LDV technique, more powerful measurement technique for local steam flow rates can be developed.