Abstract: An aid of a jet injector includes a first pinching piece and a second pinching piece that face each other, and pinches a skin in a state of holding the skin with pinching surfaces facing each other and thus forms a fold shape part where the skin is raised in a fold shape; and a reception portion that is provided in the first pinching piece, exposes a fold top part vicinity region, which is a region in a vicinity of a fold top part, in the fold shape part, and can receive the nozzle portion of the jet injector.

Abstract: An image display device has: a display 4 for displaying a video image; a backlight 3 for illuminating the display 4; a level detector 6 for detecting level of a video signal; a video signal adjuster 5 for adjusting a video signal to a signal of a level adapted to be displayed by the display 4; and a microcomputer 1, based on a signal from the level detector 6, for decreasing illuminance of the backlight 3 when the level of the video signal is low and increasing illuminance of the backlight 3 when the level of the video signal is high. The microcomputer 1 has a timer function and has a correcting function, when the low level of the video signal detected by the level detector 6 continues more than predetermined time, for increasing one of the level of the video signal and a brightness level of the display 4 by controlling the video signal adjuster 5.