The present invention provides: a spreading agent for agrochemicals, the spreading agent having particularly exceptional adhesion to plant surfaces； and an agrochemical spray liquid in which the risk that residue of the spreading agent for agrochemicals will remain on the plant surfaces is reduced. The present invention pertains to a spreading agent for agrochemicals, the spreading agent containing a carboxy-group-modified vinyl alcohol polymer (A) in which the content amount of monomer units having carboxy groups is 0.1-10 mol%, the viscosity-average polymerization degree is 200-5000, and the saponification degree is 65-99.9 mol%.本發明提供一種尤其是對於植物表面的固著性優良的農藥用展著劑、及降低了該農藥用展著劑對於植物表面的殘留風險的農藥散布液。本發明係關於一種農藥用展著劑，其含有羧基改性乙烯醇系聚合物(A)，該羧基改性乙烯醇系聚合物(A)是具有羧基之單體單元的含有率為0.1莫耳%以上10莫耳%以下、黏度平均聚合度為200以上5000以下，且皂化度為65莫耳%以上99.9莫耳%以下。
