Abstract: Mixer bucket (1) provided with a hopper (12) having a concave bottom portion (120) provided with an opening (122) arranged between a first and a second continuous portions (124)(126); a funnel-shaped member (30) being carried by the concave portion (120) so as to face the opening (122) and define a gravity discharge for mixture; the funnel-shaped member (30) being carried by the hopper (12) by means of a guide (128) aligned with the given direction (D); actuating means (40) being carried by the hopper (12) to move the funnel-shaped member (30) along the guide (128) between a first position (P1), where it faces the opening (122), and a second position (P2)(P3), lateral with respect to the opening (122) in correspondence of one of the first and second flanks (14)(16).