A novel dilatant fluid which keeps fluid state within a broad temperature range, is excellent in storage stability, has large mechanical strength and shows large changing quantity of viscosity resistance accompanied by the increase of shear stress. It was found that excellent dilatancy is expressed markedly specifically in a composition comprising (B) from 0.5 to 100 parts by weight of a particle dispersing agent and (C) from 5 to 1,000 parts by weight of a silicone medium, based on (A) 100 parts by weight an inorganic fine particle having a primary particle size of from 2 nm to 30 .mu.m.