Measurement of mass flow rate of polymer powder in a gas-solids pipe how was investigated theoretically and experimentally. The measurement was based on the static electrification of the flowing particles. In the system, two current detecting pipes made of different materials were used and mass flow rates were calculated from the two generated currents. Since polymer powder formed a stiff coating layer on the hard surface of metallic pipes by particle collision, several polymer materials were examined as to the detecting pipes and the performance of the current detection was evaluated by changing the powder flow rate. It was found that electrically conductive polymers containing carbon had superior stability for the current detection. It was also found that the mass flow rate of polymer powder could be measured by use of two different conductive polymers for the detecting pipes.