A developing device includes a development unit, a developer amount detector, an accuracy requirement determiner, and a detection count setting unit. The development unit includes a developer container configured to store a developer. The development unit is configured to supply the developer from the developer container to a latent image bearer, on which an electrostatic latent image is to be formed according to image data, to form a developer image. The developer amount detector is configured to detect a developer amount in the toner container of the development unit in every detection period. The accuracy requirement determiner is configured to a determine accuracy requirement required as a detection accuracy of the developer amount by the developer amount detector. The detection count setting unit is configured to set a number of times of detection of the developer amount by the developer amount detector based on the accuracy requirement.