To provide a technology whereby a user can simply grasp whether or not voice data are encrypted or subjected to like processing on a speech by an IP phone.

An IP phone adaptor 11 includes: an encryption processing section 7 for applying encryption/decryption to a speech of voice data by the IP phone; and a display means 13 for displaying a speech state by the IP phone in a state of the voice data encrypted by the encryption processing section 7. The display means 13 comprises an LED to carry out state display depending on lighting, blinking, and a difference or the like between light emission colors.