A controller for a machine tool and a five axis simultaneous control machine tool which can improve machining accuracy in controlling a pivoting axis of the machine tool. The controller including an allowable position error setting member setting an allowable position error between a commanded machining position and an actual machining position; a velocity control parameter deciding member deciding a velocity control parameter of the pivoting axes of the A-axis and the B-axis in accordance with the allowable position error being set and a distance of said actual machining position from the pivoting axes; and a controlling member controlling a velocity of the pivoting axes based on the velocity control parameter.