A controller for a servomotor capable of improving accuracy of positioning and quality of a machined surface by switching modes of correction of a position command or the like, and reducing a shock at the time of switching. A correction amount generating section obtains a correction amount based on a value of a correction factor such as machine temperature. When the external signal is in ON state, a position command or the like is corrected by the correction amount obtained by the correction amount generating section and sent via switches. A correction amount holding section holds the correction amount obtained by the correction amount generating section. When the external signal turns to OFF state, the connection of the switches is changed so that correction is performed by the correction amount held in the correction amount holding section. When the connection of the switches is changed, the correction amount does not change rapidly, so that the machine does not suffer a shock. In positioning, the external signal is turns to ON state, so that the positioning is carried out accurately by performing correction by the correction amount sent from the correction amount generating section. When a high-quality machined surface is required, the external signal is turned to OFF state so that the correction amount does not change to achieve improvement in the quality of a machined surface.