The present invention discloses a data access device and method applicable to a processor. An embodiment of the data access device comprises: an instruction cache memory; a data cache memory; a processor circuit configured to read specific data from the instruction cache memory for the Nth time and read the specific data from the data cache memory for the Mth time, in which both N and M are positive integers and M is greater than N; a duplication circuit configured to copy the specific data from the instruction cache memory to the data cache memory when the processor circuit reads the specific data for the Nth time; and a decision circuit configured to determine whether data requested by a read request from the processor circuit are stored in the data cache memory according to the read request.