A line condition data collecting system for a telephone exchange includes an image memory in a central processing unit which stores line condition data to reduce the amount of time the central controller in the central processing unit waits for the line condition data. A signal receiving memory in the telephone exchange stores the line condition data and is sequentially accessed by an image memory controller autonomously from the central controller in the central processing unit. When the central controller requires line condition data, the image memory is checked and if the line condition data stored therein is valid, it is supplied to the central controller. If the line condition data in the image memory is invalid, a conventional access request is made to the signal receiving memory, but this occurs less frequently than in a conventional system.