PURPOSE: To quickly sort a large quantity of records exceeding the capacity of an internal memory by successively reading out records from an external storage means and arranging designated keywords in the order of priority level related to designation and adding storage position information to convert records into sort records.

CONSTITUTION: A designating means (b) arbitrarily designates plural keywords as the sort object and priority levels of respective sort processings of these keywords. A converting means (c) successively reads out records from an external storage means (a) to convert them into sort records where keywords designated by the designating means (b) are arranged in the order of priority level related to designation and storage position information in the external storage means (a) is added. Sort records converted by the converting means (c) are stored in an internal storage means (d). A sorting means (e) sorts records based on sort records in the internal storage means (d). Thus, the record form is changed to perform the sort processing, and records are quickly sorted.