This Paper proposes a binary image sensor for motion detection. The sensor detects motion vectors using block-matching method. Each pixel of the image sensor has a shift register. Exclusive OR(XOR) circuits in each pixel compare the shifted image of the previous frame and the image of the current frame. The outputs of the XOR circuits are converted to current value. The current-sum circuits calculate the current-sum of pixel outputs. The current-sum of a matching block represents the sum of absolute difference. The motion vector is obtained by routine of shifting image of the previous frame and comparing the sum of absolute difference. The chip was fabricated using 1.2um 2-Metal 2-Poly-Si CMOS technology and composed of 32 × 32 pixel array and peripheral circuits in a 7.3mm × 7.3mm die.