Provided is a device for preventing information leakage including: a storage unit that stores message time, request source information, and request destination information in relation to each information requesting message; a unit that suspends a response message containing personal information in response messages in response to the information requesting messages, for a predetermined suspended time from a message time of the corresponding information requesting message; a unit that counts the number of information requesting messages transmitted from the same request source to the same destination and corresponding to the suspended response message on the basis of information stored in the storage unit; and a unit that, in the case where the counted number of the information requesting messages exceeds a predetermined threshold value, applies a protection process to the suspended response message so that the personal information contained in the suspended response message is not received by the request source.