The invention relates to an adapted toe-piece of a ski binding (1) for also allowing walking uphill, comprising: a first clamping member (21) which is rotatable and which is provided with a first jaw (31); a second clamping member (22) which is rotatable and which is provided with a second jaw (32); a first rotatable support (61) which rotatably bears the first clamping member (21) and which is in turn rotatable; a second rotatable support (62) which rotatably bears the second clamping member (22) and which is in turn rotatable. In the ski descent configuration (D), the first jaw (31) and the second jaw (32) can elastically retract if solicited by the tip (3) of the ski boot. The first clamping member (21) is also provided with a third jaw (33) and the third jaw (33) is provided with a first pin (51); the second clamping member (22) is also provided with a fourth jaw (34) and the fourth jaw (33) is provided with a second pin (52). The toe-piece of a ski binding (1) also comprises locking means (10) which when the tip (3) of the ski boot is between the third jaw (33) and the fourth jaw (34), the blocking means are activatable to block the third jaw (33) and the fourth jaw (34) in angular blocking positions in which the first pin (51) is inserted in the first hole of the ski boot and the second pin (52) is inserted in the second hole of the ski boot, making walking uphill possible.