The invention provides a single photon avalanche diode type pixel circuit, which comprises a plurality of sub-pixel arrays, and is characterized in that the sub-pixel arrays receive the same control signal and realize synchronous operations; and each sub-pixel array comprises a plurality of single photon avalanche diode type pixel unit and a time-to-digital converter, the single photon avalanche diode type pixel units in the same row are connected to the same input row control signal and the same output row control signal, the single photon avalanche diode type pixel units in the same column are connected to the same input column control signal, the same output row control signal and the same output gating signal, and the output end of each single photon avalanche diode type pixel unit is connected to the same time-to-digital converter. According to the single photon avalanche diode type pixel circuit, a pixel array is divided into a plurality of sub-pixel arrays, the pixel units in each sub-pixel array share the same time-to-digital converter, so that the light-sensing area duty ratio can be greatly increased, the pixel size is reduced, and the resolution of an image sensor is improved.