The invention relates to a device and a process for detecting faces in a colour image. The process is such that it comprises the steps of: detection of the flesh coloured pixels in the image, segmentation of the image into regions of homogeneous colour, selection, among the regions of homogeneous colour, of the regions comprising a number of flesh coloured pixels greater than a first predetermined threshold, the regions selected being said to be flesh coloured regions. merging of the neighbouring flesh coloured regions until the merge cost attains a second predetermined threshold, the merge cost linearly weighting a merge cost relating to the shape of the regions and a merge cost relating to the colour of the regions, exclusion of false positives.