An apparatus for optically checking the exterior quality of bulbous or vegetable products of various shapes and sizes, comprises means (12) for conveying a succession of fruit or vegetable products (1) along a path from an entry (2) to an exit (3) of the apparatus and a first observation station (4) positioned along the path and provided with at least a primary camera (40) in such a way as to define a primary field of view (41) for the observation of a first segment (42) of the path. A second observation station (5) is positioned along the path downstream of the first observation station (4) and is provided with at least a secondary camera (50) in such a way as to define a secondary field of view (51) for the observation of a second segment (52) of the path separate from the first segment (42). Means for upsetting the fruit or vegetable products (1) are structured in such a way as to act exclusively in a third segment (62) of the path interposed between the first and the second segment (42, 52), therein upsetting every fruit or vegetable product (1) from a first position, in which a first surface portion (10) of the fruit or vegetable product (1) falls within the primary field of view (41) when the fruit or vegetable product (1) is in the first segment (42) of the path, to a second position, in which a second surface portion (11) of the fruit or vegetable product (1), at least complementary to the first surface portion (10), falls within the secondary field of view (51) when the fruit or vegetable product is in the second segment (52) of the path.