PURPOSE: To provide the title resin compsn. which gives moldings which have excellent impact resistance, etc. and scarcely causes warpage by extrusion, by mixing an arylene sulfide resin with a calcium alkali metal metaphosphate fibrous material.

CONSTITUTION: An arylene suflide resin (A) (e.g.,, polyphenylene sulfied) is mixed with a calcium alkali metal metaphosphate fibrous material (B) having a diameter of 1W5μm and a fiber length of 50W500μm in such a proportion that the quantity of the component B accounts for 5W80wt.% of the combined quantity of the components A and B to obtain a desired arylene sulfide resin compsn. The component B is prepared, for example, by melting Na2O or Li2O, P2O5 and CaO, keeping the molten mixture at 500W780°C to crystallize it, cooling it, bringing it into contact with water to dissolve soluble matters, recovering an insoluble matter and fiberizing it.