PURPOSE: To improve storage stability and flowability of a suspension in an aqueous medium by compounding a natural rubber and two kinds of specific polymers with a water-insoluble solid organic peroxyacid.

CONSTITUTION: Components A-C described hereinafter are suspended into an aqueous medium to prepare a bleaching composition. (A) a water-insoluble solid organic peroxyacid (example: 1,12-diperoxide decanoic diacid, coated with a water-impermeable substance such as lauric acid, myristic acid): quantity to come within 1-200ppm. preferably 2-100, of active oxygen content in a used liquid, (B) polymers, (b1) a natural rubber (preferably xanthane gum), 0.1-1w%; (b2) a polyvinyl alcohol or cellulose derivative (preferably a cellulose ether such as a methylcellulose or carboxymethylcellulose), 0.02-2%: (C) an electrolyte (taking account of physical stability and handling property, example: Na2SO4), up to 30w%.