The invention relates to a portable device (1) for amplifying an axial force applied to a tool, which includes: means (100) for linking the device to a user; means (2) for guiding the tool (4) it translation along a longitudinal axis (X); means for actuating the tool, including a drain (5) provided with a motor (6) and a rope (7) rigidly connected to the tool (4) and forming at least one turn (8) around the drum (5); and means for controlling the actuating means in order to apply a force to the tool in response to a force provided by the user via a control member. The means (100) for linking, tile device to the user and the means (2) for guiding the tool (4) in translation allow the tool (4) to rotate freely about the longitudinal axis (X) and about at least one axis (Z, Y) extending in a plane (P) which is normal to the longitudinal axis (X).