PURPOSE: To obtain a beautiful vessel painted in an yellow or blown color by molding a sheet into a vessel, which is formed by foaming at a specific value of density a composition obtained by adding a fine powder of fibrous materials that pass through at least a specific sieve to olefin resin at a specific quantity.

CONSTITUTION: A resin composition is made by adding a fine powder of a fibrous material to an olefin resin. The fibrous materials are put through a sieve of 10 meshes and only materials which have passed through the sieve are used. Fine powder of the fibrous materials are added to 100 pts.wt. olefin resin at a rate of 0.1-50 pts.wt. At 0.1 pts.wt. or lower, a coloring effect can not be obtained adequately, and at 50 pts.wt. or higher, it becomes hard to be dispersed into the olefin resin uniformly. A mixture of the olefin resin and the fibrous material are heated and kneaded, for example, in an extruding machine, after that, it is extruded into a sheet after press-inserting a foaming agent therein for obtaining a foamed sheet through a foaming process and molding it into a vessel. Besides, the foaming agent is employed at an appropriate range to allow the density to be 0.6-0.025g/cm3.