In an image sensor, an analog-to-digital conversion circuitry generates image data by sequentially performing analog-to-digital conversion processing twice or more on a pixel signal transferred from the pixel array in an operation period of one horizontal cycle, and an image signal processing circuitry receives the image data and performs digital processing on the image data. A timing controller controls the image signal processing circuitry to hold the digital processing during a plurality of holding periods that respectively correspond to portions of two or more ADC processing periods.