Wild pollinators contribute to enhance the pollination of Brassica napus (oilseed rape) and thus increase its market value. Several studies have shown that pollination services are greater in crops adjoining forest patches or other semi-natural habitats than in crops completely surrounded by other crops. In this study we investigated the importance of forest edges in providing potential pollinators to Brassica napus fields in two areas in France. Bees were caught with yellow pan traps at different distances from forest edges inside Brassica napus fields during the blooming period. A total of 4,000 individual bees, representing six families and 82 species (or genera) were collected. We found that both bee abundance and species richness were negatively affected by the distance from forest edge. However, responses differed between species, sex and life history traits. There was a greater abundance of cuckoo bees of Andrena spp. (Nomada spp.) and Andrena spp. males at forest edges, which we assume is linked to the local availability of nesting and mating sites. Forest edges seem to play a different role for another speciose family, Halictidae, by providing a diversity of floral resources or establishing a corridor between nesting sites and the forage crop. Furthermore, the mean body size of the species seems to limit how far the bees can travel from the forest edge. Our findings indicate that forest edges are potential early spring pollinator sources for Brassica napus. It might be useful to take into account crop size and forest edge length when planning crop rotation systems and landscape management to promote wild bees and their pollination services.