There is provided a modified zirconium phosphate tungstate which effectively suppresses the elution of phosphorus ions even when it contacts with water, can develop the performance excellent as a negative thermal expansion material, and can be dispersed in a polymer compound such as a resin, and use of which enables a low-thermal expansive material containing a negative thermal expansion filler to be well produced. The surface of a zirconium phosphate tungstate particle is coated with an inorganic compound containing one or two or more elements (M) selected from Zn, Si, Al, Ba, Ca, Mg, Ti, V, Sn, Co, Fe and Zr. The BET specific surface area of the zirconium phosphate tungstate particle is preferably 0.1 m2/g to 50 m2/g.