A memory device has a variable storage capacity depending on the object of use by a user, thereby improving convenience in use of the device. The memory device has a casing which may be loaded into host equipment. The casing has a plural number of loading sections in each of which a memory chip can be mounted. The casing carrying the memory chips has a terminal unit at the end insertable in the host equipment. Data readout from or writing into the memory chip is controlled by a semiconductor unit forming a control circuit disposed in the casing. The memory device may be of a recording capacity as desired by a user by changing the number of the memory chips mounted in the loading sections or by mounting memory chips of variable recording capacities in the loading sections.