Provided is a liquid decontaminant composition, containing the following: component (A), component (B), component (C), and component (D), wherein the content of the component (A) is 0.5-20% by mass calculated by the total mass of the component (A),(B),(C), and (D), the content of the component(B) is 0.2-8% by mass calculated by the total mass of the component (A),(B),(C), and (D), the content of the component(C) is 1.0-20% by mass by the total mass of the component (A),(B),(C), and (D), and the sum of the contents of the component (A), the component (B), and the component (C) is 1.7-30% by mass calculated by the total mass of the component (A),(B),(C), and (D). Mass ratio of the content of the component (A) and the component (B) is 2/1 to 20/1. (A) is a polyoxyethylene alkyl ethers nonionic surfactant represented by a formular (1), R1O-(CH2CH2O)n-H... (1), wherein R1 represents a linear chain or branched chain alkyl group or alkenyl with 10-14 carbon atoms, and n represents a digit of 85-150. (B) is a linear chain or branched chain saturated or unsaturated higher aliphatic acid salt with 8-16 carbon atoms. (C) is polyhydric alcohols with 3-6 carbon atoms. (D) is water.
