The invention relates to a device for payment by banker's card including an electronic circuit allowing identification of the bearer and authentication of the card. On acquisition, the bearer inserts two codes c1 and c2, supplied by the authorised body, into two memories which become unmodifiable subsequently. In order to use his card, the bearer makes up his two codes, the comparison of which with those contained in the memory generates, or does not generate, the display of a message of the "valid" type, thus confirming his identity. In order to test the validity of the card, the shop keeper inserts three codes V0, V1 and V2 and compares what results therefrom with a fourth code V3 which is also supplied to him. The card is fitted with an overall circuit cutoff triggered by the succession of a preset number of attempts at introducing invalid codes C1, C2 or triplets V0, V1, V2. Deducing the code C1 knowing C2 or vice versa is made impossible since each card contains an adder systematically adding an unknown number to C1. Pirating of this card is made impossible by resin contacts in the circuit, being destroyed with the least damage to the housing. The card contains an internal battery inserted on manufacture serving as a relay to an interchangeable battery, the charge state of which allows operation of the circuit and possibly neutralisation of it by operating the circuit cutoff. The recording of the debit is done with the traditional "scraper" and withdrawal of money in automatic cash dispensers by virtue of the chip.