Labor-saving-type water-buoyant agrochemical compositions are provided for direct application to paddy fields. The agrochemical compositions comprise each not only at least an agrochemically active component and a surface-active agent, but also (1) bubbles and/or dents besides a carbonate and a solid acid, (2) closed type hollows having a bulk density of less than 1, or (3) closed type hollows having a bulk density of less than 1, a binder and a disintegrating agent, wherein a density of the composition is less than 1 g/cm<;3>;. The agrochemical compositions have the following characteristics: they will float on the surface of paddy water after being thrown into flooded paddy fields, distribute the agrochemically active components, leave no agrochemical-treated traces on the surface of soils at the sites where the agrochemicals are applied, and be freed from localized, efficacies.