A bearing unit for agricultural use, the bearing unit comprising: a rolling bearing, a housing body for the rolling bearing, and a sealing device for preventing the entry into the rolling bearing of contaminants. The sealing device in turn having, at least on one side of the rolling bearing, a first sealing level defined by at least one sliding-contact sealing lip and a second sealing level arranged in series with the first sealing level along an axis of symmetry of the rolling bearing. The sealing device defining a labyrinth for preventing the entry of contaminants into the first sealing level.