PROBLEM TO BE SOLVED : To access medical information on a health care apparatus via a communication network. SOLUTION : This health care device 10 includes a web server 14 for transferring a message with a web client by using HTTP(hyper text transfer protocol) and HTML(hyper text mark-up language) open protocol. The server 14 processes an HTTP command designating a prescribed URL of the device 10. The HTTP command is used by a client to read measured data and optional medical information, including optional related information from the device 10. The server 14 constitutes the medical information to an HTML format and transfers this information to the web client which requests an HTTP protocol through its use. A health care person at an arbitrary place accessable to internet can make access to measured data and related information of the device 10 by using a web browser 40.