A bleach composition containing (a) a peroxide generating hydrogen peroxide by being dissolved in water, (b) a water-insoluble or poorly water-soluble textile powder selected from powder cellulose, silk powder, wool powder, nylon powder, and polyurethane powder, and (c) (c-1) a bleaching activating catalyst and/or (c-2) a bleaching activator. A bleaching detergent composition containing (a) a peroxide generating hydrogen peroxide by being dissolved in water, (b) a water-insoluble or poorly water-soluble textile powder selected from powder cellulose, silk powder, wool powder, nylon powder, and polyurethane powder, and (c) (c-1) a bleaching activating catalyst or (c-1) a bleaching activating catalyst and (c-2) a bleaching activator, and (d) a surfactant.