A pesticidal composition including a microcapsule in which an oil containing a pesticidal active ingredient and an organic solvent is covered with a wall material made of a thermosetting resin, a sorbitan fatty acid ester, a thickener, and water is provided. The pesticidal composition has elution performance suited for an applied situation without the need of changing the design of the microcapsule itself As the thermosetting resin, a polyurethane resin or a polyurea resin is preferred. As the pesticidal active ingredient, an insect growth regulating active ingredient such as 4-phenoxyphenyl2-(2-pyridyloxy)propyl ether is recited.