A semiconductor device and search circuit for and method of searching for a count of erasures in a semiconductor memory. The semiconductor device includes a semiconductor memory in which data erasure is performed in units of blocks. A block management memory stores, corresponding to each of the blocks, a piece of erasure count data representing a count of erasures of data performed in the block. An erasure count search circuit successively reads the pieces of erasure count data from the block management memory so as to search for a block corresponding to a piece of erasure count data representing an intended erasure count from among the pieces of erasure count data read from the block management memory. The circuit also outputs an address of the searched block as an erasure count address.