A time series data display device calculates position data in time-series of a movement point on drive axes based on the position feedback data, generates a command movement trajectory of the machine end based on the position command data, generates an actual movement trajectory of the machine end based on the actual position data, calculates position data of the machine end which are intersection points between straight lines, which are perpendicular to the command movement trajectory and pass through the movement point, and the actual movement trajectory, converts the position data of the machine end to position data with respect to drive axes, and displays the position feedback data in time-series and the position data in time-series.