An imaging device includes a first image sensor that is placed to intersect the optical axis of an imaging lens, a second image sensor that is placed to intersect the optical axis of the imaging lens so as to be situated at a given distance from the first image sensor, and receives light that has passed through the first image sensor, and a processor including hardware, wherein the processor is configured to implement a brightness correction process that amplifies the pixel value of the second image captured by the second image sensor using a gain set based on the light transmittance of a light-receiving section of the first image sensor, and an object distance calculation process that performs a depth-from-defocus (DFD) process based on the pixel value of the first image and the pixel value of the second image subjected to the brightness correction process to calculate an object distance.