To efficiently perform a packing work by saving labor when a bag body is fitted in a housing box, and to easily and quickly close the upper opening of the bag body after a product or an article is housed in the fitted bag body, and to efficiently perform the packing work.

For this housing box having a bag, a lid body is provided at least on one side plate being confronted with each other of the housing box which can be folded into a flat shape by folding back a paper material. Then, at least one engaging part is formed by cutting out on the lid body. The upper part of the bag body being fitted in the housing box is engaged with the engaging part.