Critical speed analysis was conducted for a active steering bogie prototype, developed to improve the curving performance of railway vehicles. The critical speed for the design concept was about 169.2 ㎞/h. To validate the analysis result, we performed a critical speed test for the prototype bogie using a roller-rig tester. The test results showed that the critical speed for the prototype bogie was about 165 ㎞/h. From the analysis and test results, The critical speed for the prototype bogie was determined to be 165 ㎞/h. Considering the maximum operating speed of the test vehicle is 100 ㎞/h, the prototype bogie is considered stable.