Water-based urethane resin composition and synthetic leather

The present invention provides a water-based urethane resin composition characterized by comprising: a urethane resin (A) which is a reaction product obtained from starting materials indispensably comprising a polyol (a1), a reactive silicone (a2) having a number-average molecular weight of 4,000 or higher and having a functional group that reacts with an isocyanate group, and a polyisocyanate (a3); and an aqueous medium (B). The present invention further provides a synthetic leather characterized by including a skin layer and/or surface treatment layer formed from the water-based urethane resin composition. The problem to be solved by the invention is to provide a water-based urethane resin composition excellent in terms of wear resistance and hydrolytic resistance. The water-based urethane resin composition of the present invention is suitable for use as the skin layers or surface treatment layers of synthetic leathers.