A semiconductor memory device includes a pixel array having pixels, a logic circuit configured to process a signal output by the pixels to generate image data, and sensor pads connected to the logic circuit, where the sensor pads include a first ground sensor pad, a second ground sensor pad, signal sensor pads disposed between the first ground sensor pad and the second ground sensor pad and configured to output the image data, and dummy sensor pads disposed between the first ground sensor pad and the second ground sensor pad and configured not to output the image data, and at least one of the dummy sensor pads is disposed between the signal sensor pads.