To enable providing smooth running of railcars and proper operation of an emergency brake by calculating a thrust command value from detected acceleration value and an acceleration command value, supplying power to a motor by calculating voltage and current values from thrust command values calculated, thereby instantaneously judging the running conditions of a train.

An acceleration command value output from an acceleration command section 1 and a measured value of acceleration detected by an acceleration detecting section 2 for detecting the acceleration of a train are input to an acceleration subtracting section 3. The acceleration subtracting section 3 subtracts the difference between an acceleration command value and acceleration measured value, and the result is input to an acceleration control section 4. The acceleration control section 4 amplifies this deference, calculates a thrust command value in such a manner that the acceleration measured value finally becomes as close as possible to the acceleration command value, and the result is input to a polarity discriminator 5. The discriminator 5 judges the polarity of thrust command value, and braking (B) command is input to a power converter 6. The power converter 6 receives an input from the polarity discriminator 5 and supplies a required command value to a motor 7 mounted on a train 8.