Method and device for converting analog signals, of a plurality of pathways, into digital signals. A common circuit (2, 3) generates first analog signals corresponding to high-order bits of digital signals. For each pathway, a first means compares the first analog signals with the signal to be converted. A first means (18) stores high-order bits corresponding to the value of a first analog signal close to the signal to be converted. A means (9) stores the deviation between the analog signal to be converted and said first detected value. A generator means (11, 12) generates a predetermined number of second analog signals. A second means compares by successive approximations said second analog signals with said deviation. A means (20) stores said low-order bits corresponding to the results arising from said second means of comparison. A means (22) assembles said high-order bits and said low-order bits.