To provide inexpensive communication interface equipment that the time- sequential data or past data of equipment being the target of communication are obtained without making it necessary for a personal computer to be always connected with the communication interface equipment and to repeatedly transmit a request.

This communication interface equipment is provided with a communication command storing means 5 for storing a communication command to be transmitted to equipment 2 being the target of communication for connecting the target equipment 2 with a communication network interposed between the target equipment 2 and a personal computer 3 which operates the target equipment 2, or monitors the operation, and operating signal conversion between the target equipment 2 and the communication network, a communication command transmitting means 6a for transmitting the communication command stored in the communication command storing means 5 to the target equipment 2, a response storing means 4 for storing the response of the target equipment 2 to the communication command, and a response transmitting means 6b for reading the response stored in the response storing means 4 and transmitting the response to the personal computer 3 based on a request from the personal computer 3.