A device is disclosed for use in positioning an instrument for use in a surgical procedure. The device comprises a mechanical positioning mechanism (2) configured to couple to the instrument (15) outside of a patients body for movement relative to the patients body. The mechanical positioning mechanism (2) includes a first movement assembly (200) coupled to a first bearing component (46) to allow pivoting of the instrument through a pivot point (11) about a first axis (Y). A second movement assembly (204) is mounted on the first movement assembly (200) and coupled to a second bearing component (51) to allow the instrument to pivot through the pivot point (11) about a second axis (X). A guide element (210) is operable in conjunction with the second movement assembly (204) to constrain the instrument to pivot about the second axis (X). The guide element (210) is spaced apart from the axis of the first bearing component (46). The device also includes a control mechanism to cause the positioning mechanism (2) to move the instrument (15) by transmitting force applied by a human from the control mechanism to the positioning mechanism (2).
