To enable a medical worker to easily recognize frame lines indicated on a display screen of a display and changing in color by work hours without sacrificing a character display portion as little as possible regardless of how a nurse call base unit is installed.

An angle detector 4 for detecting the angle of the display screen and a work-hour-determining part 5 for determining the work hours are attached to the nurse call base unit 1. When the angle of the display screen in the up-and-down direction is approximately vertical, the display screen in which the upper frame line of the frame lines whose color varies by the work hours is bold is indicated. When the display screen is approximately horizontal, the display screen in which the lower frame line of the frame lines is bold is indicated. Consequently, in a board-type unit, the width of the upper frame line is indicated larger, so that all the frame lines may be visible even when the display screen is looked down obliquely from above. In a desktop-type, the width of the lower frame line is indicated larger, so that all the frame lines may be visible even when the display screen is looked up from below.