A film supplying apparatus for holding two film rolls (Ra, Rb), joining the end of a first film reeled out from one (Ra) of the film rolls and the end of a second film reeled out from the other film roll (Rb) to each other, and supplying the two joined films as an elongate film, comprising: film holding means holding the beginning end of said first or second film in a standby state; film joining means disposed near said film holding means, for joining said films to each other in a joining position; film feeding means for reeling in from a film roll at least one of said first and second films in use; tape detecting means for detecting a tape applied to a seam joint of said first and second films; cutting means for cutting off a portion of said film in use which is disposed upstream of a joined region thereof, in a cutting position which is disposed downstream of said tape detecting means with respect to the direction in which said film is fed; and a rotary support supporting two roll holding members (76, 77) on which said film rolls (Ra, Rb) are rotably mounted, said rotary support being rotatable about a support shaft to positionally reverse said film rolls through 180°; characterized in that the film supplying apparatus further comprises a pair of guide roller groups (86a-86e) disposed on a circumferential surface of said rotary support extending around a center coaxial with said support shaft in symmetrical position, one (86a-86e) for guiding said first film and the other (86a-86e) for guiding said second film; wherein said rotary support is selectively movable between a first in-use posture in which said first film is a film in use and in which said second film (1 B) is a standby film and a second in-use posture which is reversed 180° from said first in-use posture and in which said first film is a standby film and said second film is a film in use; wherein said cutting means cuts off a portion of said film in use which is disposed downstream of said tape, based on a detected result from said tape detecting means; said film joining means joins the cut end of said film in use and the end of said first or second film held in the standby state, to each other. film holding means holding the beginning end of said first or second film in a standby state; film joining means disposed near said film holding means, for joining said films to each other in a joining position; film feeding means for reeling in from a film roll at least one of said first and second films in use; tape detecting means for detecting a tape applied to a seam joint of said first and second films; cutting means for cutting off a portion of said film in use which is disposed upstream of a joined region thereof, in a cutting position which is disposed downstream of said tape detecting means with respect to the direction in which said film is fed; and a rotary support supporting two roll holding members (76, 77) on which said film rolls (Ra, Rb) are rotably mounted, said rotary support being rotatable about a support shaft to positionally reverse said film rolls through 180°; characterized in that the film supplying apparatus further comprises a pair of guide roller groups (86a-86e) disposed on a circumferential surface of said rotary support extending around a center coaxial with said support shaft in symmetrical position, one (86a-86e) for guiding said first film and the other (86a-86e) for guiding said second film; wherein said rotary support is selectively movable between a first in-use posture in which said first film is a film in use and in which said second film (1 B) is a standby film and a second in-use posture which is reversed 180° from said first in-use posture and in which said first film is a standby film and said second film is a film in use; wherein said cutting means cuts off a portion of said film in use which is disposed downstream of said tape, based on a detected result from said tape detecting means; said film joining means joins the cut end of said film in use and the end of said first or second film held in the standby state, to each other.