A controller and a machining path generation device for wire-cut electric discharge machine, capable of improving the machining accuracy of a reentrant corner portion subjected to multi-path machining. The controller or machining path generation device is provided with machining program storage means for storing a machining program, offset amount storage means for storing a wire offset amount foreach machining operation, machining program analysis means for analyzing the machining program, machining shape definition means for creating a machining shape of a workpiece based on the result of an analysis by the machining program analysis means, machining shape correction circular-arc radius storage means for storing a predetermined circular-arc radius used to correct the machining shape, and circular arc insertion means which eliminates opposite end portions of a reentrant corner portion formed of two intersecting nonparallel motion blocks and inserts a circular-arc motion block with the predetermined circular-arc radius into the eliminated portion if the machining shape defined by the machining shape definition means includes the reentrant corner portion.