To prevent water from entering between a window body 20 and a transparent cover 30 of an instrument 10 and water droplets from being adhered to the surface of the window body 20 even if the transparent cover 30 thereof is used for a long time, and to permit easy reading of measured values indicated on the indication part 12 of the instrument 10.

The inner side surface 32 of a transparent cover 30 is adhered to a window body 20, and the outer side surface 34 thereof is on the same plane as the outer surface 16 of a housing 14, or it is projecting over the outer surface 16 thereof.