A foot lock ascender for ascending along a rope including a swivelling gate and attachment portion including at least a first passage for a first strap to pass through and to be adjusted, and at least a second passage for a second strap to pass through. The first strap is inclined by a predefined angle with respect to the throat, the angle is between 40° and 75° so as to keep the bottom of the throat parallel to the path of the rope when ascending.