A digital controller for controlling a plurality of processes. In view of the fact that in case a plurality of processes of a like nature are to be controlled, same operands are used for performing a similar arithmetic operation a number of times, instructions are stored in a common memory for simplifying the programming, while the operands are stored in memories each incorporated in each of the processors adapted for controlling individually the objective processes, to thereby allow arithmetic processings to be performed by the processors in parallel with one another. Overall processing speed is made thus significantly high.