A guide wire control device for advancing a guide wire into a body or a portion of the body, comprises a handle member (1), a lever (2) and a spring means (3). The spring means (3) holds the lever (2) relative to the handle member (1) such that the longitudinal axis of a through-hole (9) in the lever (2) is misaligned with the longitudinal axis of an elongate passage (4) in the handle member (1) for locking the guide wire control device to a guide wire (5) extending through said elongate passage and said through-hole. Pivotal movement of the lever (2) brings the longitudinal axis of the through-hole (9) into alignment or substantial alignment with the longitudinal axis of the elongate passage (4) for release of the guide wire (5). Pivotal movement of the lever (2) also brings the longitudinal axis of the through-hole (9) into renewed misalignment with the longitudinal axis of the elongate passage (4) for clamping of the guide wire (5).
