The object of the invention is to provide an aqueous coating agent which I applied onto a recording medium in the ink-jet system to form a film excellent in scratch resistance, water resistance and gloss on the surface of an image, and an aqueous coating solution containing this aqueous coating agent. The means for solving is an aqueous coating agent for pigment ink-jet, which is characterized by comprising a graft copolymer that has a silicone-based side chain, and an ethylenically unsaturated carboxylic acid-containing monomer as an essential constituent in a main chain, and has an acid value in the range from 40 to 200 mg-KOH/g (solid) and a weight-average molecular weight in the range from 5,000 to 30,000; and an aqueous coating solution for pigment ink-jet comprising the aqueous coating agent which is characterized in that the aqueous coating solution is charged into a tank different from a tank for pigment ink, and is ejected and applied onto a recorded material from a nozzle different from a nozzle for pigment ink in ink-jet system.