An information terminal apparatus includes: a communication unit for transmitting/receiving information among the communication means, a server of a credit card firm, and a server owned by a settling financial institution which settles a charge requested from the credit card firm; a processor for executing a comparison process as to both credit card charge historical information issued from the credit card firm and balance account information saved in the settling financial institution, the credit card charge historical information being contained in the transmission/reception information of the communication unit; and an output unit for outputting predetermined information based upon the comparison process result by the processing means.