Abstract: An optical keyboard comprising: a flat optical block whose top face (9) is intended to co-operate with the keys (12); light inlets (2) and light detection outlets (3) having intersections (4) which couple one light inlet with one light detection outlet; key-actuated elements situated at the intersections for coupling or decoupling the inlets and the outlets; optical ducts which are unobstructed from a corresponding light inlet to a corresponding matrix intersection, and from a corresponding matrix intersection to a corresponding light detection outlet; and a scanning stage for applying a signal successively to each of the inlets and for observing the state of each of the outlets after each signal application; is characterized in that the light inlets and the light detection outlets are disposed along the same one of the sides (31) of said optical block, with each key emplacement being directly connected to a single light emitter and a single light receiver via respective optical ducts (2, 3).