The present invention provides a semiconductor device that can reduce the power consumption, including: a plurality of search memory cells arranged in a matrix; a plurality of match lines provided corresponding to each memory cell row to determine match/mismatch between data stored in the search memory cell and search data; a plurality of match line retention circuits provided corresponding to each of the match lines; a storage unit for storing information relating to the state of each of the match lines; and a selection circuit for selectively activating the match line retention circuits based on the information stored in the storage unit.