An imaging device comprising: a pixel array unit; a detection unit that is configured to receive images taken by the pixel array unit and to detect that a specific region in an image taken by the pixel array unit is a region of interest; a control unit that is configured to perform control to read out a pixel signal at first pixel resolution in a region including the region of interest and read out a pixel signal at second pixel resolution lower than the first pixel resolution in a region not including the region of interest; and a plurality of analog-digital conversion units (14, 141) each of which being provided corresponding to one vertical signal line of the pixel array unit, the plurality of analog-digital conversion units (14, 141) converting pixel signals read out by the control unit into digital signals, wherein a plurality of pixels in the pixel array unit is defined as a pixel unit, wherein the plurality of pixels in the pixel unit shares one vertical signal line between the pixels and includes control switches (SW1, SW2, SW3, SW4) that selectively connect the pixels to the vertical signal line, and and wherein the control unit is configured to selectively set a second operation mode in which signals of the plurality of pixels in the pixel unit are sequentially read out and supplied via the vertical signal line of the pixel unit to the analog-digital conversion unit (14, 141) corresponding to said vertical signal line and a first operation mode in which signals of the plurality of pixels are added and read out as a signal of one pixel supplied via the vertical signal line of the pixel unit to the analog-digital conversion unit (14, 141) corresponding to said vertical signal line, and the control unit sets the second operation mode for the region of interest and sets the first operation mode for a region other than the region of interest, the control unit selectively sets the first operation mode and the second operation mode by on/off controlling each of the control switches (SW 1, SW 2, SW 3, SW 4) of the plurality of pixels. a pixel array unit; a detection unit that is configured to receive images taken by the pixel array unit and to detect that a specific region in an image taken by the pixel array unit is a region of interest; a control unit that is configured to perform control to read out a pixel signal at first pixel resolution in a region including the region of interest and read out a pixel signal at second pixel resolution lower than the first pixel resolution in a region not including the region of interest; and a plurality of analog-digital conversion units (14, 141) each of which being provided corresponding to one vertical signal line of the pixel array unit, the plurality of analog-digital conversion units (14, 141) converting pixel signals read out by the control unit into digital signals, wherein a plurality of pixels in the pixel array unit is defined as a pixel unit, wherein the plurality of pixels in the pixel unit shares one vertical signal line between the pixels and includes control switches (SW1, SW2, SW3, SW4) that selectively connect the pixels to the vertical signal line, and and wherein the control unit is configured to selectively set a second operation mode in which signals of the plurality of pixels in the pixel unit are sequentially read out and supplied via the vertical signal line of the pixel unit to the analog-digital conversion unit (14, 141) corresponding to said vertical signal line and a first operation mode in which signals of the plurality of pixels are added and read out as a signal of one pixel supplied via the vertical signal line of the pixel unit to the analog-digital conversion unit (14, 141) corresponding to said vertical signal line, and the control unit sets the second operation mode for the region of interest and sets the first operation mode for a region other than the region of interest, the control unit selectively sets the first operation mode and the second operation mode by on/off controlling each of the control switches (SW 1, SW 2, SW 3, SW 4) of the plurality of pixels.