To provide a movable sinker member constituted by combining a sinker body and a spring member which are formed so as to be easily assembled; and a flat knitting machine having a movable sinker device using the movable sinker member.

There is provided a movable sinker member α used for the movable sinker device turnably attached to the tip of a comb gap side of a needle bed 1 in a flat knitting machine 100. The movable sinker member α includes: a plate-like sinker body 4 for pressing down fabric by acting on a sinker loop of the fabric engaged with a knitting needle 3 of the needle bed 1 when rotating in one direction around the center of a support part 42 serving as a rotary axis; and a filigree spring (a spring member) 5 engaged with the sinker body 4, for urging the sinker body 4 in one direction around the rotary axis. The sinker body 4 and the spring member 5 are engaged together by caulking.