Systems to acquire borehole data during the drilling of oil and gas wells make use of measurement while drilling (MWD). One feature of this system is that it is able to do real-time measuring from a borehole; therefore there has been a lot of MWD use on drilling sites in recent years. There are a few types of MWD. Mud pulse-type MWD, which uses a drilling circuit fluid, is superior to the rest because of its reliability, accuracy of data, and less disturbance of the drilling schedule. The drilling circuit fluid is raised to a high pressure by a mud pump; borehole data which are recorded by the surface measuring system are contaminated by the pumping noise. Therefore, it is necessary to remove the pumping noise to get objective data. This report describes the pumping noise removal system and the method used for the telemetry system from 2000 m depth.