To shorten the time consumed from generation of dissolved detergent liquid to its transfer and to provide a simple structure not using a siphon mechanism for making the detergent liquid flow.

In a detergent dissolving device provided with a detergent dissolving chamber and a detergent agitating rotary body placed inside the detergent dissolving chamber, the detergent agitating rotary body is provided with the function of generating the dissolved detergent liquid of high concentration by mixing powder detergent and water, and the function of transferring the generated dissolved detergent liquid.