A compression bag includes longitudinally continuous sheets continuously supplied in a longitudinal direction to lie one upon another, and adhered at predetermined spots to form an article containing portion having a space for an article and an air passageway having a space continuing to the space of the article containing portion. The sheets include a frontal sheet, a rear sheet which is equal to the frontal sheet in breadth (i.e., the transverse side dimension of the sheets), at least one valve body sheet disposed between the frontal and rear sheets and made smaller than the front and rear sheets in breadth, and base members disposed between at least one of the frontal and rear sheets and the valve body sheet and made smaller than the valve body sheet in breadth.