Disclosed is a detergent storing assembly and washing machine using the same, by which a lid part and a detergent box constructing the detergent storing assembly are correctly assembled to each other. The present invention includes a tub having an open front side to hold water and detergent, a drum rotatably installed in the tub to hold laundry, a motor rotating the drum, a cabinet having the tub and the motor inside, and a detergent storing assembly at the cabinet to provide the detergent to detergent to the tub. And, the detergent storing assembly includes a detergent box having an open topside to store the detergent and to provide the detergent to the tub for washing, a lid part fixed to the topside of the detergent box to open/close, and an incorrect-assembling preventing means for leading the lid part to a correct position for a reciprocal assembling of the lid part and the detergent box.