A fixing device includes a fixing rotator and a pressure rotator that is disposed opposite the fixing rotator. A nip former is disposed inside a loop formed by the fixing rotator and disposed opposite the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The fixing rotator slides over the nip former. A flange supports the fixing rotator at both lateral ends of the fixing rotator in a longitudinal direction of the fixing rotator. The nip former includes a base and a thermal conductor that has a thermal conductivity greater than a thermal conductivity of the base. The base is greater than the thermal conductor in the longitudinal direction of the fixing rotator. The base includes a groove that is disposed outboard at least from the thermal conductor in the longitudinal direction of the fixing rotator.