PURPOSE: To eliminate limitations regarding the shapes of hollow articles and facilitate reduction of production costs by producing a resin hollow article by heating to melt a resin core and causing the melt to flow out of the hollow article made of a second resin whose melting point is higher than that of the core resin.

CONSTITUTION: A core 1 formed of a first resin into a desired shape is set in a desired mold. A second resin body 2 is formed by injecting a second resin having a higher melting point than the first resin. The resultant resin molding is then set in a suitable heating furnace and heated to a predetermined temperature that is higher than the melting point of the first resin but lower than the melting point of the second resin body 2. After the first resin of the core 1 is completely melted by the heating process, a predetermined fluid is blown to a blow surface from a heating device 5 through a blow tube 50 that has been fixed to an opening of the second resin body 2. The molten first resin is thereby forced to flow out of the second resin body 2 and then it is removed. After being cooled, the hollow article is taken out of the heating furnace 4.