To provide a stain-resistant triangular corner capable of saving time and effort of washing.

In the triangular corner, a bottom surface and one side surface of a triangle are removed. The triangular corner formed of two side surfaces with an right angle interposed therebetween is not placed in a sink, but fixed in a corner in the upper part of the sink. A garbage bag is put on the triangular corner, and brought into a suspended state. In order to prevent the garbage bag from slipping due to an increase in weight of garbage, it is stopped by a clothespin. The triangular corner formed of the two surfaces with the right angle interposed therebetween without a bottom enables spacious use inside the sink, and eliminates the need for washing. Since a wide triangular inlet is formed when the garbage bag is put on, garbage can be easily put in, and moreover, the garbage bag can be replaced easily.