A machining program editing assist apparatus includes a display controller. While the display objects are being displayed in either one of the program data display area and the process list display area, the display controller decides that a designated display object of the one of the display areas is the display object designated by the display objects of the one of the display areas and a specific point, differentiates the designated display object from the other display objects in the one of the display areas, decides that a designated display object of the other of the display areas is the display candidate of the other of the display areas, includes the designated display object in the display objects of the other of the display areas, and differentiates the designated display object from the other display objects in the other of the display areas.