To provide a digital composite machine having improved security in rewriting user-designated information.

The digital composite machine 1 can rewrite user-designated information by a series of inputted operations using two or more key operations. The composite machine 1 includes: a key operation input section 6 having two or more input keys 12 and used to perform a predetermined operation input by a key operation to each of the input keys 12; a user-designated information storage section 8 for storing the user-designated information; a fingerprint reading section 14 for repeatedly reading the fingerprints of an operator as read information; a registered data storage section 5 for storing previously registered fingerprints as registered data; a user authenticating section 4 for comparing the read information with the registered data and authenticating the user on the basis of a result of comparison; and a user-designated information updating section 7 for rewriting the user-designated information into information designated by a series of operations on the basis of a result of authentication by the user authenticating section 4 per key operation in a series of operation inputs.