A gas supply control device for an apparatus, particularly a coking apparatus, includes timing means (20) and a first command means (12) for manually setting a an opening time interval of a safety valve of a gas tap (1), equipped with a second command means (6). In an installed condition of the control device (10), the command means (6, 12) are operable from outside the structure (7) of the apparatus, with the first command means (12) and the second command means (6) substantially rotating around one same axis, one independent from the other. The timing means (20) of the control device (10) belong to a functional unit (10a) which is coupled or configured for coupling with a portion of the body of the tap (2) which portion, in the above mentioned installed conditions, is located inside the structure (7) of the apparatus. The functional unit (10a) includes switch means (22), controllable by timing means for cutting off the electric current to a solenoid of the tap (1) at the end of a time interval set through the first command means (6), and hence causing the passage of the valve to the respective closed condition.