The invention relates to a unit for dispensing a product comprising a case (1) and a cassette (2) which has a zone for dispensing (7) the product conditioned in a reservoir of said cassette, said cassette intended to be arranged in a housing (3) formed in a body of said case by arranging said dispensing zone in an access window (8) which is formed in an upper wall (4) of said body, said unit comprising a reversible locking mechanism of the cassette (2) in the housing (3) which has a frame (27) mounted in horizontal translation in said housing by being maintained vertically, said frame and said cassette being provided with complementary means which are arranged to, in a first position of the frame (27), allow for the arranging of the cassette (2) in the housing (3) with the dispensing zone (7) in the window (8) and, in a second position of said frame, lock the position of said cassette in said housing.