Aqueous surface treatment agent and product using same

The present invention provides an aqueous surface treatment agent and a product using the same, the aqueous surface treatment agent characterized by containing an aqueous polyurethane (A) having a 100 percent modulus of 10-20 MPa, and a carbodiimide-based crosslinking agent (B). This aqueous surface treatment agent includes essentially no organic solvents, is capable of imparting excellent abrasion resistance to the surfaces of various products such as synthetic leather and polyvinyl chloride (PVC) leather, and does not decrease the bendability of such products as synthetic leather. The aqueous surface treatment agent may be configured so as to further contain a filler (C) when a matte finish is to be imparted to the surface of a product such as synthetic leather to achieve a high-grade design.