To provide a cutting device which cuts sealed base films produced by a bag making machine for forming the base films into a bag by sealing prescribed places of the films one by one into bags and simultaneously rounds the edges of the bags.

The device for cutting the sealed base films in each of which a plurality of baglike parts are formed continuously by sealing prescribed domains of at least two base films laid to overlap each other includes a conveyance means for conveying the sealed base film, a slitting means for slitting the sealed base films arranged at a prescribed position in the width direction of the sealed base films being conveyed in a prescribed place, a conveyance route separation means for separating the conveyance route of the sealed base films after being slit, and a cutting edge rounding means which is arranged at a prescribed position in the conveyance direction of the sealed base films after the conveyance route is separated, cuts the sealed base films one by one into the bags, and simultaneously rounds the edge parts of the bags.