To provide a repeater, a repeating method, a program for demonstrating a repeating function and a computer readable information recording medium in which the program for demonstrating the repeating function is recorded capable of enhancing reliability of security by prohibiting a communicating origin from performing data communication with a communcating destination by disguising a position of itself.

The repeater 1 repeats the data communication between the communicating origin 11 and the communicating destination 5 based on a repeating request from the communicating origin 11 to the communication destination 5. The repeater 1 is provided with a receiving means 41 for receiving the repeating request from the communicating origin 11 in which a position that the communicating origin 11 asserts as the position of itself is included and repeating means 42, 43 without starting repeating to the communicating destination 5 when the position that the communicating origin 11 asserts as the position of itself is originally in the outside of a repeatable area 4 of the data communication and for starting the repeating to the communicating destination 5 only when the position is within the repeatable area 4 of the data communication.