A solid-state image pickup device (30, 152) for performing switching between a plurality of AD conversion resolutions by changing a comparison time period during which a pixel signal output from a pixel and a ramp signal, whose level changes in a ramp form during the comparison time period, are compared with each other, comprising: a first counter which is configured to count, if a second counter does not count; the second counter which is configured to count, if the first counter has stopped counting; storage means for storing a number of counts as a specific and preset count value representing a difference between a comparison time period for a first resolution that is the lowest resolution among the plurality of AD conversion resolutions and a comparison time period for a second resolution that is different from the first resolution, and a specific and preset start count value that is a count value of the first counter at which counting by the first counter is stopped and counting by the second counter is started; and counter control means for stopping counting by the first counter and starting counting by the second counter (i) when a set AD conversion resolution is the second resolution and (ii) the actual count value of the first counter reaches the specific and preset start count value and for resuming counting by the first counter when the actual count value of the second counter reaches the specific and preset count value. a first counter which is configured to count, if a second counter does not count; the second counter which is configured to count, if the first counter has stopped counting; storage means for storing a number of counts as a specific and preset count value representing a difference between a comparison time period for a first resolution that is the lowest resolution among the plurality of AD conversion resolutions and a comparison time period for a second resolution that is different from the first resolution, and a specific and preset start count value that is a count value of the first counter at which counting by the first counter is stopped and counting by the second counter is started; and a number of counts as a specific and preset count value representing a difference between a comparison time period for a first resolution that is the lowest resolution among the plurality of AD conversion resolutions and a comparison time period for a second resolution that is different from the first resolution, and a specific and preset start count value that is a count value of the first counter at which counting by the first counter is stopped and counting by the second counter is started; and counter control means for stopping counting by the first counter and starting counting by the second counter (i) when a set AD conversion resolution is the second resolution and (ii) the actual count value of the first counter reaches the specific and preset start count value and for resuming counting by the first counter when the actual count value of the second counter reaches the specific and preset count value. for stopping counting by the first counter and starting counting by the second counter (i) when a set AD conversion resolution is the second resolution and (ii) the actual count value of the first counter reaches the specific and preset start count value and (i) when a set AD conversion resolution is the second resolution and (ii) the actual count value of the first counter reaches the specific and preset start count value and for resuming counting by the first counter when the actual count value of the second counter reaches the specific and preset count value.