The present invention is a data processing apparatus including a data input/output device for receiving data, a storage for storing the data received by the data input/output device, a data processing program storage for storing a data processing program that includes the steps of calculating, using a double exponential smoothing method, a first predicted value that is a predicted value of smoothed data and a second predicted value that is a predicted value of the gradient of the smoothed data, and calculating, using a double exponential smoothing method in which the second predicted value is set as input data, a third predicted value that is a predicted value of smoothed data and a fourth predicted value that is a predicted value of the gradient of the smoothed data, and a data calculation processing apparatus for performing the data processing under the data processing program.