Concrete mixer

The utility model provides a concrete mixer and solves the problems of a concrete mixer in the prior art that materials are not completely discharged when the materials are conveyed. The concrete mixer comprises a rack, an agitating barrel, a feeding hopper, a discharging hopper and a driving device, wherein the feeding hopper is hinged to the rack through a feeding hopper hinging shaft; a limiting part is arranged at one end of the feeding hopper hinging shaft; a limiting baffle is arranged below the limiting part; the limiting baffle is connected with a connection sleeve; the limiting baffle is connected with a feeding handle; the connection sleeve is connected with an inner disc of a braking disc; an outer disc of the braking disc is connected with a rotary sleeve; one end of a steel wire rope is connected onto the rotary sleeve and the other end of the steel wire rope goes around a direction changing wheel and the feeding hopper to be connected with a main shaft of the direction changing wheel; a first vi