An image forming apparatus includes an image carrying member, a charging device that uniformly charges the image carrying member, an exposure device that forms an electrostatic latent image on the image carrying member, a development device that applies a development bias voltage to form a visible image in which toner is adhered to the electrostatic latent image, a control portion that controls an exposure amount in the exposure device and the development bias voltage and a storage portion that stores an exposure condition and a development condition. The resolution of image data can be switched to at least two types, a standard resolution and a high resolution higher than the standard resolution, and when the resolution of the image data is set at the high resolution, the control portion controls the exposure amount in the exposure device to perform thinning processing on the image.