We propose a system that detects the current speaker in multi-speaker videoconferencing by using lip motion. First, the system detects the face and lip region of each of the candidate speakers using face color and shape information. Then, to detect the current speaker, it calculates the change between the current frame and the previous frame in lip region. To close-up the detected current speaker, we used two CCD cameras. One is a general CCD camera, the other is a PTZ camera controlled by RS-232C serial port. The experimental result is the proposed system capable of detecting the face of current speaker in a video feed with more than three people, regardless of orientation of the faces. With this system, it only takes 4 to 5 seconds to zoom in on the speaker from the initial reference image. Also, it is a more efficient image transmission system for such things as video conferencing and internet broadcasting because it offers a close up face image at a resolution of 320x240, while at the same time providing a whole background image.