PURPOSE: To obtain readily a foamed and molded item using exsisting facilities, adding a radical former and a foaming agent to an olefin resin, extruding the mixture in the uncrosslinked and unfoamed state into a sheet, and heating the sheet to be molded into a prescribed shape while the plasticizing, crosslinking and foaming are being effected.

CONSTITUTION: For example, to 100pts. low-density polyethylene is added 42W 82pts. wood powder, 210pts. foaming agent and a minor amount of a radical former, and the mixture is stirred in a tumbler or the like, and is extruded by an extruder at a temperature not higher than 130°C into a sheet. The resulting sheet is heated by the irradiation of infrared rays or the like to 230°C (at least a temperature at which the foaming starts) so that it is plasticized and the crosslinking reaction and foaming are initiated, and it is set in a pressing machine, and is press molded.