PURPOSE: To provide a dispersing agent giving an insecticidal aqueous suspension having sufficient storage stability, low viscosity and good flowability by incorporating a specific compound such as a polyethylene glycol styrene oxide adduct into the dispersing agent.

CONSTITUTION: A dispersing agent for suspending insecticides comprises a compound of formula I [Z is the residue of a p valent active hydrogen-containing compound; p is 1-8; A is 2-4C alkylene; Y is group of formula II (R, R' are H, alkyl or halogen), III (R'' is alkyl) or V; n is 0-1000, but at least one of the n among p kinds of n is ≥1 and three or more of the Y exist in the molecule]. A suspended insecticide composition contains 0.1-40wt.% of the dispersing agent, 5-70wt.% of an insecticide and 20-80wt.% of an aqueous medium as essential components. The composition has good flowability even at a high concentration.