A developing roller has a surface layer composed of a binder resin having an SP value in the range of 7.5 to 9.0, and roughness-imparting particles made from a resin having an SP value that has a difference from the SP value of the resin of 2 or less in the absolute value thereof. The roughness-imparting particles are dispersed in the binder resin. A developing device is provided with the developing roller. An image-forming apparatus is provided with the developing device equipped with the developing roller.