The invention provides an activation device for a neural network processor and a processor. The activation device comprises a lookup table unit, an activation control unit, a lookup preprocessing unitand a lookup post-processing unit, wherein the lookup table unit stores a corresponding relation between an independent variable value and a function value of an activation function type; the activation control unit is used for generating a control signal for the lookup table preprocessing unit and the lookup post-processing unit according to a currently selected activation function type; the lookup preprocessing unit is used for obtaining a to-be-searched value according to the control signal and the to-be-activated neuron value x; the lookup table unit is used for finding a function value matching the value to be looked up from a corresponding relation between an independent variable stored in the lookup table unit and an activation function value of the independent variable to serve asa lookup value; and the lookup post-processing unit is used for obtaining an activation result of the to-be-activated neuron value x according to the control signal and the lookup value.