A bag making and packaging machine sandwiches a tubular film between a first horn and a first anvil and ultrasonically transversely seals it. The bag making and packaging machine includes: a knife disposed in an anvil-side knife movement space formed in the first anvil; a knife-driving part, and guides provided to each of two ends of the first anvil, on which guide spaces, by which movement of the knife is guided when the knife is driven by the air cylinder, are formed. The width of the guide spaces with respect to a direction orthogonal to both a length direction and a movement direction of the knife is less than the width of the anvil-side knife movement space with respect to the same direction.