An imaging element includes: a plurality of pixels configured to receive light from outside and generate and output an imaging signal depending on an amount of the light received； a first transfer line connected to the pixel； a second transfer line； a column selection switch configured to select one pixel column and output the imaging signal to the second transfer line； a column source follower including a gate to which the imaging signal transferred by the first transfer line is input, a drain end being connected to a power supply voltage, and a source end being connected to the column selection switch； a constant current source configured to drive the column source follower and read out the imaging signal to the second transfer line； and a current generating unit configured to flow a predetermined current to the source end side of the column source follower.
