Disclosed is an anomaly data detection device, which includes a sampler that generates session data including first to m-th sample data based on input data input during a first time interval, a spike signal generator that generates first to m-th spike signals respectively corresponding to the first to m-th sample data based on the session data, a spike neural network that detects whether an output spike fires in at least one output neuron from among output neurons based on the first to m-th spike signals and synaptic weights of each of the output neurons, and a detection circuit that generates a detection signal based on the number of output neurons firing the output spike, and each of the first to m-th spike signals is generated by converting feature information of the corresponding first to m-th sample data into a spike rate code.