An image sensor comprising: a first color separation element (150; 151, 152; 153; 154) configured to separate an incident light, the incident light being separated into a mixture of a first color light and a third color light, and separated into a second color light; and a sensor array unit (110; 120) comprising a plurality of pixels configured to sense the separated incident light, the sensor array comprising a first pixel region and a second pixel region that are alternately arranged in a first direction and a second direction, the second direction crossing the first direction, wherein a stack of a first light sensing layer (112; 122), configured to sense the first color light, and a third light sensing layer (116; 126), configured to sense the third color light, is provided in the first pixel region, and a second light sensing layer (114; 124) configured to sense the second color light is provided in the second pixel region, wherein the first color separation element (150; 151, 152; 153; 154) is disposed at a position facing the second pixel region, configured to allow the second color light to pass through the first color separation element (150; 151, 152; 153; 154) and travel in a third direction toward the second pixel region, and configured to allow the mixture of the first color light and the third color light to pass through the first color separation element (150; 151, 152; 153; 154) and travel in a fourth direction slanted with respect to the third direction, further comprising a second color separation element (160; 161, 162; 163; 164) disposed to face the first pixel region, configured to allow the mixture of the first color light and the third color light to pass through the second color separation element (160; 161, 162; 163; 164) and travel in a fifth direction toward the first pixel region, and configured to allow the second color light to pass through the second color separation element (160; 161, 162; 163; 164) and travel in a sixth direction slanted with respect to the fifth direction, the first and second color separation elements are alternately arranged along the first or second direction. a first color separation element (150; 151, 152; 153; 154) configured to separate an incident light, the incident light being separated into a mixture of a first color light and a third color light, and separated into a second color light; and a sensor array unit (110; 120) comprising a plurality of pixels configured to sense the separated incident light, the sensor array comprising a first pixel region and a second pixel region that are alternately arranged in a first direction and a second direction, the second direction crossing the first direction, wherein a stack of a first light sensing layer (112; 122), configured to sense the first color light, and a third light sensing layer (116; 126), configured to sense the third color light, is provided in the first pixel region, and a second light sensing layer (114; 124) configured to sense the second color light is provided in the second pixel region, wherein the first color separation element (150; 151, 152; 153; 154) is disposed at a position facing the second pixel region, configured to allow the second color light to pass through the first color separation element (150; 151, 152; 153; 154) and travel in a third direction toward the second pixel region, and configured to allow the mixture of the first color light and the third color light to pass through the first color separation element (150; 151, 152; 153; 154) and travel in a fourth direction slanted with respect to the third direction, further comprising a second color separation element (160; 161, 162; 163; 164) disposed to face the first pixel region, configured to allow the mixture of the first color light and the third color light to pass through the second color separation element (160; 161, 162; 163; 164) and travel in a fifth direction toward the first pixel region, and configured to allow the second color light to pass through the second color separation element (160; 161, 162; 163; 164) and travel in a sixth direction slanted with respect to the fifth direction, the first and second color separation elements are alternately arranged along the first or second direction.