An image pickup system (1, 1A) comprising: an image pickup device (2, 2A) having a photodetecting section with a plurality of pixels (P M,N) arranged two-dimensionally therein, each pixel (P M,N) comprising a first photodiode (PD 0, 61) arranged to output image data that represents the two-dimensional intensity distribution of light incident on said photodetecting section, each pixel (P M,N) further comprising second and third photodiodes (PD 1, 62; PD 2, 63) arranged, respectively, to output light intensity profile data that represents the one-dimensional intensity distribution of the incident light in each of a first direction and a second direction different from the first direction in said photodetecting section; a peak position detecting section configured to acquire the light intensity profile data in the respective first and second directions outputted from said image pickup device (2, 2A) and detect a plurality of light intensity peak positions in the two-dimensional intensity distribution of the light incident on said photodetecting section in said image pickup device (2, 2A) based on the acquired light intensity profile data; a partial image acquiring section (4, 4A) configured to acquire a partial image from each of a plurality of entire images (A 0) that can be imaged by the image pickup device (2, 2A) so that the light intensity peak positions detected by said peak position detecting section are made specific positions for the partial image in each of the plurality of entire images (A 0); and a partial image operating section configured to add a plurality of partial images acquired from the plurality of entire images (A 0) by said partial image acquiring section (4, 4A) to display an integrated image obtained as a result of the addition on a display section. an image pickup device (2, 2A) having a photodetecting section with a plurality of pixels (P M,N) arranged two-dimensionally therein, each pixel (P M,N) comprising a first photodiode (PD 0, 61) arranged to output image data that represents the two-dimensional intensity distribution of light incident on said photodetecting section, each pixel (P M,N) further comprising second and third photodiodes (PD 1, 62; PD 2, 63) arranged, respectively, to output light intensity profile data that represents the one-dimensional intensity distribution of the incident light in each of a first direction and a second direction different from the first direction in said photodetecting section; a peak position detecting section configured to acquire the light intensity profile data in the respective first and second directions outputted from said image pickup device (2, 2A) and detect a plurality of light intensity peak positions in the two-dimensional intensity distribution of the light incident on said photodetecting section in said image pickup device (2, 2A) based on the acquired light intensity profile data; a partial image acquiring section (4, 4A) configured to acquire a partial image from each of a plurality of entire images (A 0) that can be imaged by the image pickup device (2, 2A) so that the light intensity peak positions detected by said peak position detecting section are made specific positions for the partial image in each of the plurality of entire images (A 0); and a partial image operating section configured to add a plurality of partial images acquired from the plurality of entire images (A 0) by said partial image acquiring section (4, 4A) to display an integrated image obtained as a result of the addition on a display section.