An apparatus and method to decrease bit rate through direct control of video compression parameters when compressing a video. The video compressing apparatus may use a Region of Interest (ROI)-dependent compression parameter and may include a ROI estimating part, a parameter allocating part, and a compression part. The ROI estimating part may estimate theROI of an input video. The parameter allocating part may allocate a compression parameter to each region of the input video based on the estimated ROI information. The compression part may compress the input video by applying the parameter allocated to each region. A higher compression rate may be achieved by allocating a higher bit rate to the ROI and a lower bit rate to non-ROI regions.