To form a curved surface of sophisticated design, and to obtain the uniform quality by respectively inserting a plurality of tips which are colored to express hot water or cold water, and consist of a three-dimensionally formed synthetic resin into a plurality of fitting parts provided on right and left sides of an operation lever.

Fitting parts 4a, 4b to insert tips 5, 6 formed of a synthetic resin colored, for example, red and blue in their right and left sides are provided on an upper surface part of an operation lever 4 of a single lever type mixing value 1. For example, the tip 6 has a curved surface along a curved surface of an upper surface part of the operation lever 4, a side surface part 6b is suspended from an upper surface part 6a, two ribs 6c are provided perpendicular to the side surface part 6b, and a part on which the rib 6c is formed is approximately as thick as the width of the fitting part 4b so that the tip 6 is not easily detached. The upper surface part 6a of the tip 6 is flush with the curved surface of the upper surface part of the operation lever 4 by fitting the tip 6 to the fitting part 4b. The tip 5 is similarly fitted.