PURPOSE: To reduce the record capacity and also to shorten the retrieving time of contents by designating the conditions for retrieval to an optional bit group of an optional field independently of other bit groups.

CONSTITUTION: For a record style, a field 84 showing the family of a record 8 is provided. This field 84 includes the information bit 841 which shows the sex, e.g., "1" for men and "0" for women and information bits 842, 843 and 844 for a spouse, a father and a mother respectively. Here "1" and "0" show the presence and the absence respectively with said information bits. Then a mask pattern register 9 and a mask circuit 10 are provided to a condition coinsidence deciding circuit applying such a record style. Thus it is possible to use a retrieving command which can designate an effective retrieval conditions only to the value of a specific bit group excepting those which are deleted by a mask in the field. In other words, a comparator for decision of retrieval conditions can be excluded. This reduces the record capacity and also shorten the retrieving time of contents.