PROBLEM TO BE SOLVED: To provide a spreading agent for water-floating agrochemical preparations, which is excellent in spreadability as compared with the prior art. SOLUTION: This is a spreading agent for a water-floating pesticide formulation containing a nonionic surfactant (X) represented by the general formula (1), wherein the spreading agent for a water-floating pesticide formulation is contained. The number average number of methyl groups in R1 in all (X) molecules per molecule is 2.0 or more, and one molecule of n in all (X) contained in the water-surface floating type pesticide formulation spreader A water-floating type pesticide formulation extender having a number average nA per unit of 2 to 15. R1O- (AO) nB (1) [In the general formula (1), R1 represents an alkyl group having 8 to 11 carbon atoms； n AOs each independently represents an alkyleneoxy group having 2 to 4 carbon atoms； n is an integer of 0 to 200； B represents -R2 or -COR2； R2 represents an alkyl group having 1 to 2 carbon atoms. ] [Selection figure] None【課題】 本発明は従来技術に比して、拡展性に優れた水面浮遊型農薬製剤用拡展剤を提供することを目的とする。【解決手段】 一般式（１）で表される非イオン性界面活性剤（Ｘ）を含む水面浮遊型農薬製剤用拡展剤であって、前記水面浮遊型農薬製剤用拡展剤が含有する全ての（Ｘ）におけるＲ１中のメチル基の１分子あたりの数平均個数が２．０以上であり、前記水面浮遊型農薬製剤用拡展剤が含有する全ての（Ｘ）におけるｎの１分子あたりの数平均ｎＡが２～１５である水面浮遊型農薬製剤用拡展剤。 Ｒ１Ｏ－（ＡＯ）ｎＢ （１）［一般式（１）中、Ｒ１は炭素数８～１１のアルキル基を表し；ｎ個あるＡＯはそれぞれ独立に炭素数２～４のアルキレンオキシ基を表し；ｎは０～２００の整数であり；Ｂは－Ｒ２又は－ＣＯＲ２を表し；Ｒ２は炭素数１～２のアルキル基を表す。］【選択図】なし
