A flatbed knitting machine with a yarn feeding device , the flatbed knitting machine includes: at least two needle beds interleaving a needle bed gap to face each other in a front-back direction and having knitting needles to be lined up in a lengthwise direction; a carriage being capable of reciprocating along the lengthwise direction of the needle beds and being mounted with a knitting cam to sequentially select the knitting needles and to drive for knitting a knitted fabric; yarn feeder rails being installed above the needle bed gap and having tracks to extend in the lengthwise direction of the needle beds; wherein the carriage being provided with an entrainment pin which is capable of being engaged with an entrainment-type running member mounted on the track and causes the entraining-type running member to run while being engaged; and the yarn feeding device including a self-running-type running member mounted on the track and capable of running in the lengthwise direction on a part of a route formed by the track for feeding knitting yarn to the knitting needles: and the yarn feeding device comprises; a movement member that has a movement part extending in the lengthwise direction, is arranged in parallel to an outer side of the track in the front-back direction with a distance between the movement member and the track; a coupling member that couples the self-running-type running member to the movement part; and a movement driving part that is provided on an end portion of the yarn feeder rail in the lengthwise direction and is capable of driving the self-running-type running member to run on the track by driving the movement member in the lengthwise direction and thereby moving the coupling member ; characterized in that the self-running-type running member mounted on the track can be interleaved in a distance in the front-back direction between the movement part of the movement member and the track . at least two needle beds interleaving a needle bed gap to face each other in a front-back direction and having knitting needles to be lined up in a lengthwise direction; a carriage being capable of reciprocating along the lengthwise direction of the needle beds and being mounted with a knitting cam to sequentially select the knitting needles and to drive for knitting a knitted fabric; yarn feeder rails being installed above the needle bed gap and having tracks to extend in the lengthwise direction of the needle beds; the yarn feeding device comprises; a movement member that has a movement part extending in the lengthwise direction, is arranged in parallel to an outer side of the track in the front-back direction with a distance between the movement member and the track; a coupling member that couples the self-running-type running member to the movement part; and a movement driving part that is provided on an end portion of the yarn feeder rail in the lengthwise direction and is capable of driving the self-running-type running member to run on the track by driving the movement member in the lengthwise direction and thereby moving the coupling member ; characterized in that the self-running-type running member mounted on the track can be interleaved in a distance in the front-back direction between the movement part of the movement member and the track . <EOS>