An arithmetic processing apparatus includes an arithmetic circuit configured to perform an arithmetic operation on data having a first data width and perform an instruction in parallel on each element of data having a second data width, and a cache memory configured to store data, wherein the cache memory includes a tag circuit storing tags for respective ways, a data circuit storing data for the respective ways, a determination circuit that determines a type of an instruction with respect to whether data accessed by the instruction has the first data width or the second data width, and a control circuit that performs either a first pipeline operation where the tag circuit and the data circuit are accessed in parallel or a second pipeline operation where the data circuit is accessed in accordance with a tag result after accessing the tag circuit, based on a result determined by the determination circuit.