A continuous fastener element in a fastener stringer has a plurality of fine projections disposed on a circumferential surface of a monofilament continuously along a length direction of the monofilament and a plurality of recesses disposed between the projections. A cross-sectional shape of the projection is curved convexly, and a cross-sectional shape of the recess is curved concavely. A curvature of the convex curved surface of the projections is set to be larger than a curvature of the concave curved surface of the recess in a cross-section of the monofilament. At least the projections disposed on the upper and lower leg parts are twisted with respect to an extension direction of the upper and lower leg parts, and a plurality of the projections disposed on the upper leg part or the lower leg part in a twisted state face the same direction.