A search payload data shift part has n latch parts LT1 to LTn (n.gtoreq.2), each of which can store 1-byte latch data, and obtains search payload data having an n-byte length, while shifting payload data inputted from an input terminal, in synchronization with a clock provided from the exterior. Data related to the search payload data is given to a CAM array, as search object data. When the search object data matches entry data of the CAM array, a hit signal `hit` indicating a match is outputted from the CAM array.