A numerical controller looks ahead and analyzes commands indicated by a block contained in a program, and identifies a travel direction of a control target for each of the commands to calculate a time constant based on the identified travel direction. The numerical controller then sets a time constant for filter processing based on the time constant for each of the commands, and performs filter processing on command data subjected to a linear acceleration and deceleration process, based on the set time constant. The numerical controller then calculates movement of each axis for each interpolation period, based on the command data subjected to the filter processing.