Robot controller having function of predicting processing completion time of machine tool

The robot controller includes an operation command part configured to output an operation command so as to perform a first operation of conveying a workpiece from an initial position to a first position adjacent to the machine tool, a time prediction part configured to predict processing completion time of the workpiece based on a processing start signal output from a machine tool controller, a time length prediction part configured to predict time length necessary for the first operation, and a time determination part configured to determine start time of the first operation so that the first operation is completed at the processing completion time on the basis of the predicted processing completion time and time length necessary for the first operation.