An electronic display device includes measurement sensors that measure respective items, a digital display that displays the items, and a processor. The processor determines a main image related to a measurement of at least one of the items and updates a screen at first timing. Upon displaying the main image related to a measurement of an item other than the first item on the digital display, the processor determines that a sub image is related to measurement of the first item, synchronizes the first timing with update timing that is related to the main image, and simultaneously updates the main image and the sub image.