This paper describes a face detection technique that enables detection of extremely small faces such as 6 ? 6 pixel. This is the first approach to detect very low-resolution faces in the field of face detection. First, we use a conventional AdaBoost-based face detector to show that the face detection rate falls to 39% from 88% as face resolution decreases from 24 ? 24 pixels to 6 ? 6 pixels. Second, we propose a new face detection method comprising four techniques. It improves the face detection rate from 39% to 73% for 6 ? 6 pixel faces of the MIT+CMU frontal face test set. Finally, we applied our method to real world data. By merging results of some frames and judging using a threshold, we show that our method is effective for processing real world data.