The Korean Train Express (KTX) has opened to commercial traffic since 2004 at a maximum speed of 300 km/h. As the train goes faster, it is necessary to inspect and maintain the rail regularly to secure the safety and reliability of the high-speed railway. The track irregularities can affect the running behavior of the train, the riding comfort of passengers, and the safety of the running train. To prevent undesired effects of rail irregularities, it is necessary to inspect the status of the rail regularly. Fast and accurate measurement result is the key role of the rail measurement system. The authors contrived the high-speed rail measurement system with a maximum measurement speed of 320 km/h and installed it into HSR-350x. The Korea High-speed Railway (HSR-350x) was developed and is being tested. The track irregularity inspection module for HSR-350x was designed and constructed over 300 km/h. A real test run on the high-speed rail was then performed. In this paper, we introduce the track irregularity inspection system and the measurement system of HSR-350x. A test run to verify the reliability of the system is performed and the result shows good performance of the track inspection measuring system.