To provide a packaging machine which uses sealing members to sandwich and seal a packaging material, wherein the presence of articles trapped in the sealed portions can be detected even when using, as the drive source of the sealing members, a mechanism that is incapable of perceiving the force/moment exerted on the packaging material by the drive source, and positional information pertaining to the drive source, directly from information obtained from the drive source. In this packaging machine, a pair of sealing jaws (51) sandwiches and seals a sealed portion of a tubular film (Fc). The packaging machine is provided with a first rotating shaft (53a) for supporting one sealing jaw (51 a), a second rotating shaft (53b) for supporting the other sealing jaw (51 b), a rotary encoder (40), and an entrapment determination part. When the first rotating shaft and the second rotating shaft approach or move away, the rotary encoder measures the movement amount of the first rotating shaft in relation to the second rotating shaft in an approaching direction or a moving away direction. The entrapment determination part determines whether or not articles are present in the sealed portion based on the movement amount.