To improve the operability of a sewing machine by simplifying an operation for obtaining a desired gradation.

When a starting/setting key is depressed and set to start the adjusting of gradation, the control continuously successively making a display lighter is automatically and continuously repeated until gradation data become the lightest data. Then, the gradation of the display of a display device is automatically and successively changed to become a dark display and to a light display in such a manner that the gradation of the display gradually becomes lighter displays and thereafter becomes the darkest display and gradually becomes lighter displays again (S2-S6). In the case the gradation of the screen is judged to be a desired gradation, the starting/setting key is depressed and set (S7: Yes) and then present gradation data are stored in a RAM as the gradation of the display and also the changing of gradation is interrupted.