A sensor is fabricated by a two poly-four metal 0.35 μm CMOS process in order to operate in the Geiger mode. The chip consists of an 8 × 8 array of 67 × 67 μm² pixels that can be readout in either a summing mode or sequential mode. The features of the CMOS single photon avalanche photodiode (CMOS SPAD) were analyzed. The pixels were then arranged in a 8 × 8 array and the possibility of the summing mode and the sequential mode was verified. The CMOS SPAD pixel has a fill factor of 17.4%. The breakdown voltage of the pixel was at 18.9 V, and the photon detection efficiency was 20% at the 550 nm wavelength. The dead time was 20 nsec, and the dark count rate was 10 kHz at and below the single photon level. The operation of both summing mode and sequential mode function was sucessful in the 8 × 8 array sensor.