The present disclosure discloses an adder device, a data accumulation method and a data processing device. The adder device comprises: a first adder module provided with an adder tree unit, composed of a multi-stage adder array, and a first control unit, wherein the adder tree unit accumulates data by means of step-by-step accumulation based on a control signal of the first control unit; a second adder module comprising a two-input addition/subtraction operation unit and a second control unit, and used for performing an addition or subtraction operation on input data; a shift operation module for performing a left shift operation on output data of the first adder module; an AND operation module for performing an AND operation on output data of the shift operation module and output data of the second adder module; and a controller module.