An image acquisition device comprising: a light source for outputting an irradiation light; a spatial light modulator for modulating the irradiation light; a control unit for controlling a modulating pattern to be presented on the spatial light modulator so that a first light converging point and a second light converging point are formed in an observation object; a light converging optical system for converging the modulated irradiation light to form the first light converging point and the second light converging point in the observation object; a scanning unit for scanning positions of the first light converging point and the second light converging point in the observation object in a scanning direction intersecting an optical axis of the light converging optical system; a photodetector for detecting first observation light generated from the first light converging point and second observation light generated from the second light converging point; and an image creating unit for creating an image of the observation object using a detection signal from the photodetector, wherein the positions of the first light converging point and the second light converging point are different from each other in a depth direction of the observation object, wherein the scanning unit includes a light scanner configured to receive the modulated irradiation light, and wherein the light scanner is configured to receive the observation light generated at the light converging points (P1, P2) of the observation object, thereby, the observation light is de-scanned, characterized in that the photodetector includes a light detecting surface and a plurality of light detecting units on the light detecting surface, wherein a point image of the first observation light and a point image of the second observation light are formed on the light detecting surface, wherein the photodetector has a first detection area for detecting the first observation light and a second detection area for detecting the second observation light, and each of the detection areas (45a, 45b) is configured to include one or more light detection units, and wherein the sizes of the point images (P3, P4) formed on the light detection surface are different from each other. a light source for outputting an irradiation light; a spatial light modulator for modulating the irradiation light; a control unit for controlling a modulating pattern to be presented on the spatial light modulator so that a first light converging point and a second light converging point are formed in an observation object; a light converging optical system for converging the modulated irradiation light to form the first light converging point and the second light converging point in the observation object; a scanning unit for scanning positions of the first light converging point and the second light converging point in the observation object in a scanning direction intersecting an optical axis of the light converging optical system; a photodetector for detecting first observation light generated from the first light converging point and second observation light generated from the second light converging point; and an image creating unit for creating an image of the observation object using a detection signal from the photodetector, wherein the positions of the first light converging point and the second light converging point are different from each other in a depth direction of the observation object, wherein the scanning unit includes a light scanner configured to receive the modulated irradiation light, and wherein the light scanner is configured to receive the observation light generated at the light converging points (P1, P2) of the observation object, thereby, the observation light is de-scanned, characterized in that the photodetector includes a light detecting surface and a plurality of light detecting units on the light detecting surface, wherein a point image of the first observation light and a point image of the second observation light are formed on the light detecting surface, wherein the photodetector has a first detection area for detecting the first observation light and a second detection area for detecting the second observation light, and each of the detection areas (45a, 45b) is configured to include one or more light detection units, and wherein the sizes of the point images (P3, P4) formed on the light detection surface are different from each other.