Method for reading a barcode by means of an optical reader comprising a sensor having at least one line of pixels in a direction of movement provided for the optical reading device, this sensor being arranged to be able to capture, at a determined sampling frequency, a series of partial images of the barcode each formed at least on said line of pixels, the barcode comprising a plurality of bars (B1-B11) of variable widths that define a bit sequence; this method being characterised in that: A) the sensor is moved along the barcode parallel to said line of pixels at any speed of movement less than a maximum speed, wherein this maximum speed is defined so that the shift between two consecutive partial images is less than the width (X un) of the image of a bar unit of said barcode; B) the length (L cap) of said line of pixels is less than the length of the theoretical image of the barcode at the sensor and more than the width (X bm) of the image of a bar of maximum width on the sensor; C) for each partial image captured by the sensor a logical value is determined by the level of light intensity received by at least one pixel (P c) located more or less in the centre of said line of pixels; D) for each partial image captured by the sensor, the width of the bar corresponding to said logical value, when this is defined - that is to say equal to 1 or 0 - and at least when it is not identical to a logical value defined for a previous partial image, is measured when this bar is incorporated completely into this partial image; said width, when it is defined - that is to say measured and judged corresponding to an integer number of bar units - being associated with this integer number of bar units and thus with this integer number of identical bits that each have said logical value; E) when the same defined logical value is obtained for two consecutive partial images and when the width of the corresponding bar is defined, the integer number of identical bits associated with this width is retained only once for establishing said sequence of bits; said sequence of bits being formed by the succession of integer numbers of identical bits that are determined at step D), by eliminating the doublets according to step E), for said succession of partial images of the barcode. A) the sensor is moved along the barcode parallel to said line of pixels at any speed of movement less than a maximum speed, wherein this maximum speed is defined so that the shift between two consecutive partial images is less than the width (X un) of the image of a bar unit of said barcode; B) the length (L cap) of said line of pixels is less than the length of the theoretical image of the barcode at the sensor and more than the width (X bm) of the image of a bar of maximum width on the sensor; C) for each partial image captured by the sensor a logical value is determined by the level of light intensity received by at least one pixel (P c) located more or less in the centre of said line of pixels; D) for each partial image captured by the sensor, the width of the bar corresponding to said logical value, when this is defined - that is to say equal to 1 or 0 - and at least when it is not identical to a logical value defined for a previous partial image, is measured when this bar is incorporated completely into this partial image; said width, when it is defined - that is to say measured and judged corresponding to an integer number of bar units - being associated with this integer number of bar units and thus with this integer number of identical bits that each have said logical value; E) when the same defined logical value is obtained for two consecutive partial images and when the width of the corresponding bar is defined, the integer number of identical bits associated with this width is retained only once for establishing said sequence of bits;