A liquid detergent mixer includes a main body, a detergent inlet pipe, a wash water inlet pipe, and a wash water dispersing unit. The main body defines a mixing space in which wash water and liquid detergent are mixed. The detergent inlet pipe allows liquid detergent to flow into the mixing space. The wash water inlet pipe has one end protruding from the other side surface of the main body to the mixing space to allow wash water to flow into the mixing space.