A correlation operation circuit includes a first SRAM storing a plurality of pieces of detection pattern data, product-sum operators, a second SRAM storing intermediate data, and a comparator. When time series data is sequentially input, the intermediate data of all correlation functions referring to one time series data in a period during which the one time series data is input. When one time series data is input, the product-sum operator multiplies the detection pattern data sequentially read from the first SRAM by the one input time series data. The corresponding intermediate data is read from the second SRAM in synchronization with the multiplication, and the sequentially-calculated products are cumulatively added to the read intermediate data to be written back into the second SRAM as the intermediate data. As a result, the calculated correlation function data is supplied to the comparator to be compared with a predetermined specified value.