PROBLEM TO BE SOLVED: To improve sinkmarks by a method wherein a mold temperature is raised and the cooling of a surface, the finer external appearance of which is wanted to obtain, is started from the completion of the filling of a molten resin and the cooling a surface opposite to the above-mentioned surface is started when the temperature becomes lower than the glass transition temperature or the thermal deformation temperature of a using resin. SOLUTION: By cooling a molten resin injected from an injection cylinder in a cavity formed between a fixed mold 1 side and a movable mold 2 side with cooling water pipes respectively arranged on the fixed mold 1 side and on the movable mold 2 side, a desired molded article is obtained. A temperature sensor 3 is arranged in the mold so as to lower the temperature of the reproductive portion of the cavity shape on the fixed mold 1 side, which is the cavity surface raised higher than the glass transition temperature or thermal deformation temperature in order to obtain a finer external appearance, in order to sense the lowering of the temperature of the mold below the glass transition temperature or the thermal deformation temperature of a resin used. Just after the lowering, cooling water is quickly circulated on the movable mold side so as to solidify the molten resin in order to faithfully reproduce the cavity shape.
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