A pesticidal composition including a microcapsule in which an oil containing a pesticidal active ingredient and an organic solvent is covered with a wall made of a thermosetting resin; at least one kind selected from the group consisting of polyglycerin fatty acid ester, sucrose fatty acid ester and alkylbenzenesulfonic acid or its salt; 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-phenoxyphenyl 2-(2-pyridyloxy)propyl ether can be recited.