A flatbed knitting machine for pile knitting (1,21) provided with: needle beds having substantially rectangular shape with short sides and long sides, the needle beds having needle grooves parallel to the short sides arranged in a longitudinal direction parallel to the long sides, the needle beds having one of the long sides facing a needle bed gap, each needle groove inclined with a side of the needle bed gap being higher and gradually decreasing in height towards a side away from the needle bed gap; knitting needles having hooks at tips, the knitting needles respectively housed in the needle grooves with the hooks arranged on the side of the needle bed gap, the knitting needles configured to perform knitting with yarn fed from above the needle bed gap by use of the hooks advancing to and retreating from the needle bed gap; yarn feeders (9a,9b) running with a gap from each other to feed ground yarn and pile yarn as knitting yarn to the knitting needles, respectively, the ground yarn fed first and the pile yarn fed later; sinkers, tips of which having claws for ground yarn on lower side and claws for pile yarn on upper side, being driven to advance to and retreat from between the knitting needles, and capable of forming sinker loops of the ground yarn by the claw for ground yarn and being possible to form sinker loops of the pile yarn by the claw for the pile yarn respectively, while the hooks of the knitting needles drawing the ground yarn and the pile yarn to form stiches; and a sinker advancing retreating mechanism configured to drive the respective sinkers to advance to and retreat from between the knitting needles and separate the ground yarn and the pile yarn with the sinker advancing to between the knitting needles, to hook the ground yarn with the claw for ground yarn and the pile yarn with the claw for pile yarn, characterized in that the sinker advancing retreating mechanism includes capturing up-and-down means (10,30) configured to, prior to separating the ground yarn and the pile yarn, drive the sinkers to raise the tips in the needle bed gap, to capture the ground yarn fed through the yarn feeder between the claw for ground yarn and the claw for pile yarn, and to draw the ground yarn below the needle bed gap. needle beds having substantially rectangular shape with short sides and long sides, the needle beds having needle grooves parallel to the short sides arranged in a longitudinal direction parallel to the long sides, the needle beds having one of the long sides facing a needle bed gap, each needle groove inclined with a side of the needle bed gap being higher and gradually decreasing in height towards a side away from the needle bed gap; knitting needles having hooks at tips, the knitting needles respectively housed in the needle grooves with the hooks arranged on the side of the needle bed gap, the knitting needles configured to perform knitting with yarn fed from above the needle bed gap by use of the hooks advancing to and retreating from the needle bed gap; yarn feeders (9a,9b) running with a gap from each other to feed ground yarn and pile yarn as knitting yarn to the knitting needles, respectively, the ground yarn fed first and the pile yarn fed later; sinkers, tips of which having claws for ground yarn on lower side and claws for pile yarn on upper side, being driven to advance to and retreat from between the knitting needles, and capable of forming sinker loops of the ground yarn by the claw for ground yarn and being possible to form sinker loops of the pile yarn by the claw for the pile yarn respectively, while the hooks of the knitting needles drawing the ground yarn and the pile yarn to form stiches; and a sinker advancing retreating mechanism configured to drive the respective sinkers to advance to and retreat from between the knitting needles and separate the ground yarn and the pile yarn with the sinker advancing to between the knitting needles, to hook the ground yarn with the claw for ground yarn and the pile yarn with the claw for pile yarn, characterized in that the sinker advancing retreating mechanism includes capturing up-and-down means (10,30) configured to, prior to separating the ground yarn and the pile yarn, drive the sinkers to raise the tips in the needle bed gap, to capture the ground yarn fed through the yarn feeder between the claw for ground yarn and the claw for pile yarn, and to draw the ground yarn below the needle bed gap.