A device for controlling a locking/unlocking mechanism with an espagnolette, in particular of a sliding leaf (V, V'), said device allowing a manoeuvring member (2, 2') to reversibly switch the mechanism from an active locking position to an unlocking position, said device including at least one actuating shaft (11, 12) capable of being driven in rotation by said manoeuvring member, characterised in that said control device includes an angular travel converter which comprises: - a support including a cylindrical wall around a cavity in which at least one portion of said actuating shaft is inserted, and at least one aperture (103, 104) being formed in said cylindrical wall and opening into said cavity, said aperture having a shape of a circular arc slot which extends by a delimited length in the circular direction of said cylindrical wall, said slot length defining an amplitude of inactive angular travel (α2) of the manoeuvring member, and - a coupling means between said actuating shaft (11, 12) and said support, cooperating with said at least one slot (103, 104) following a path between the two respective ends (1031, 1032, 1041, 1042) of said at least one slot (103, 104), said slot ends forming bearing stops for said coupling means so as to drive in rotation said actuating shaft in an active angular travel (α1), and said coupling means including at least one protruding element (131,132) inserted into said slot (103, 104) along a path between the two respective ends (1031, 1032, 1041, 1042) of said at least one slot, said slot ends forming bearing stops for said protruding element so as to drive in rotation said actuating shaft along an active angular travel, said device being characterised in that at least said portion of the actuating shaft inserted into the cavity includes a transverse conduit, said conduit being receiver of said coupling means, and said coupling means having an elongated shape including at least one end and being of a length which is greater than that of said conduit and adapted so that said at least one end forms said at least one protruding element. - a support including a cylindrical wall around a cavity in which at least one portion of said actuating shaft is inserted, and at least one aperture (103, 104) being formed in said cylindrical wall and opening into said cavity, said aperture having a shape of a circular arc slot which extends by a delimited length in the circular direction of said cylindrical wall, said slot length defining an amplitude of inactive angular travel (α2) of the manoeuvring member, and - a coupling means between said actuating shaft (11, 12) and said support, cooperating with said at least one slot (103, 104) following a path between the two respective ends (1031, 1032, 1041, 1042) of said at least one slot (103, 104), said slot ends forming bearing stops for said coupling means so as to drive in rotation said actuating shaft in an active angular travel (α1), and said coupling means including at least one protruding element (131,132) inserted into said slot (103, 104) along a path between the two respective ends (1031, 1032, 1041, 1042) of said at least one slot, said slot ends forming bearing stops for said protruding element so as to drive in rotation said actuating shaft along an active angular travel,