To provide polyvinyl chloride, safe for a human body and having antimicrobial activities by assuming the utilization in a home, a food factory, a laboratory, a hospital, etc.

A ceramic mixture containing an antimicrobial agent in an proportion of 0.1-1.0% is added to a blended liquid such as polyvinyl chloride, which is a main material for the grove body. The ceramic mixture capable of manifesting microbicidal activities and deodorant activities by generating an active oxygen from the oxygen in air is capable of stably maintaining the activities for a long period. The inner surface of the grove is treated with a mixed solution comprising 5-15% polyvinyl chloride, 8-23% acrylic resin, 5-25% filler such as mica powder or silica powder and the balance of a polyester to prevent a plasticizer having a large stickiness from being exposed on the surface.