A yarn feeder (4,50,60) for a flatbed knitting machine provided with: a base body (1,51) that runs independently from a carriage on a running path bridged above a needle bed gap in the flatbed knitting machine; and a feeder rod (2,52,62) that droops downward from the base body (1,51), has a yarn feeder port on a lower end, moves in an up-down direction relative to the base body (1,51), capable of feeding a knitting yarn to a knitting needle from the yarn feeder port at a descended yarn feeding position, and is capable of ascending the yarn feeder port to a standby position, wherein the base body (1,51) has a pressing part (14,65), and the yarn feeder (2,52,62) further provided with a brake member (3,53,63) that is supported on the base body (1,51) so as to move relatively in a functioning range which is previously set to the base body (1,51), and has: a braking surface (31;63b) facing the running path; and a pressure receiving part (30b;63b) receiving pressure from the pressing part (14,65) at an intermediate position of the functioning range, when the pressing part (14,65) presses the pressure receiving part (30b;63b), the braking surface (31;63b) is compressed to the running path characterized in that the sliding resistance of the brake member (3,53,63) against the running path is increased to be larger than resistance received by movement of the brake member (3,53,63) relative to the base body (1,51), so that a braking state is made in which the brake member (3,53,63) stops relative to the running path even when the base body (1,51) runs relative to the running path, when the brake member (3,53,63) moves to either of both end portions (30a,30c;63a,63c) of the functioning range with movement relative to the base body (1,51), pressure from the pressing part (14,65) is reduced and the sliding resistance of the braking surface (31;63b) against the running path is reduced to release the braking state, so that the brake member (3,53,63) is entrained by the base body (1,51) so as to run, and an elevation mechanism (4a,50a,60a) that converts relative movement between the base body (1,51) and the brake member (3,53,63) into up-down movement of the feeder rod (2,52,62), and ascends the feeder rod (2,52,62) in the braking state of the brake member (3,53,63), is formed among the feeder rod (2,52,62), the base body (1,51), and the brake member (3,53,63). a base body (1,51) that runs independently from a carriage on a running path bridged above a needle bed gap in the flatbed knitting machine; and a feeder rod (2,52,62) that droops downward from the base body (1,51), has a yarn feeder port on a lower end, moves in an up-down direction relative to the base body (1,51), capable of feeding a knitting yarn to a knitting needle from the yarn feeder port at a descended yarn feeding position, and is capable of ascending the yarn feeder port to a standby position, wherein the base body (1,51) has a pressing part (14,65), and the yarn feeder (2,52,62) further provided with a brake member (3,53,63) that is supported on the base body (1,51) so as to move relatively in a functioning range which is previously set to the base body (1,51), and has: a braking surface (31;63b) facing the running path; and a pressure receiving part (30b;63b) receiving pressure from the pressing part (14,65) at an intermediate position of the functioning range, a braking surface (31;63b) facing the running path; and a pressure receiving part (30b;63b) receiving pressure from the pressing part (14,65) at an intermediate position of the functioning range, when the pressing part (14,65) presses the pressure receiving part (30b;63b), the braking surface (31;63b) is compressed to the running path characterized in that the sliding resistance of the brake member (3,53,63) against the running path is increased to be larger than resistance received by movement of the brake member (3,53,63) relative to the base body (1,51), so that a braking state is made in which the brake member (3,53,63) stops relative to the running path even when the base body (1,51) runs relative to the running path, when the brake member (3,53,63) moves to either of both end portions (30a,30c;63a,63c) of the functioning range with movement relative to the base body (1,51), pressure from the pressing part (14,65) is reduced and the sliding resistance of the braking surface (31;63b) against the running path is reduced to release the braking state, so that the brake member (3,53,63) is entrained by the base body (1,51) so as to run, and an elevation mechanism (4a,50a,60a) that converts relative movement between the base body (1,51) and the brake member (3,53,63) into up-down movement of the feeder rod (2,52,62), and ascends the feeder rod (2,52,62) in the braking state of the brake member (3,53,63), is formed among the feeder rod (2,52,62), the base body (1,51), and the brake member (3,53,63).