Powder treated with a powder treating agent comprising organohydrogenpolysiloxane, characterized in that the organohydrogenpolysiloxane has a weight average molecular weight of from 300 to 100,000, at least one SiH bond per molecule, and at least one selected from (R23SiO1/2) unit and (SiO2) unit, wherein R1 is selected from the group consisting of a hydrogen atom, and alkyl, fluorinated alkyl, aryl and aralkyl groups each having 1 to 30 carbon atoms.