The reading device enables a non-volatile memory consisting of a matrix of memory cells (TM) to be read. Once the memory cells have been selected to be read in a read cycle controlled by a microprocessor unit, sense amplifiers (4) activated at the start of each cycle supply a binary data word (dx) representing the reading of the selected memory cells. The reading device also comprises time-lag means (3, MF, TF, Cgap) activated at the start of each read cycle. These time-lag means supply a reference signal (rd_mon) that controls the read time of the cells selected independently of the microprocessor unit. This read time is determined so that it is sufficient for reading all the valid data of the selected memory cells in each read cycle.