A teaching data generator includes a storage device. An arithmetic device includes a first window display section to cause a display device to display a first window displaying first images respectively corresponding to some pieces of work unit job data stored in the storage device and included in teaching data. The first images are arranged in an execution order of pieces of work respectively corresponding to the some pieces of the work unit job data. A first job editing section performs an editing operation including replacing the some pieces of the work unit job data with other pieces of the work unit job data stored in the storage device, and changing the execution order. A teaching data generation section generates the teaching data based on a display content of the first window changed in accordance with the editing operation.