Provided is a memory device in which the circuit structure is simplified while the functions of a memory including an OTP memory and a memory including a pseudo-MTP memory are maintained. A memory device includes a plurality of memory sets each including a mark bit storage area for storing a mark bit, which indicates that an object is deleted data, and a data bit storage area for storing data, the memory device being built from an OTP memory including an OTP memory block and a pseudo-MTP memory block, the OTP memory block containing a given number of memory sets to operate as an OTP memory, the pseudo-MTP memory block containing the rest of the memory sets operates as a pseudo-MTP memory. The mark bit is written in advance in the mark bit storage area of the OTP memory block.