1. A lane detecting apparatus comprising: a region of ID setup setting a region of ID including a road region of a current lane in an acquired image; a road sign verifier verifying existence of a road sign within the set region of ID; an ROI setup calculating a difference value between a lane prediction result and previous lane information when there exists a road sign and setting an ROI based on the calculated difference value; and a lane detector detecting a lane by extracting lane markings based on the set ROI.