In recent times, light-emitting diode (LED) lighting has been widespread in offices and manufacturing buildings, but for assembly operation in manufacturing situations, it has not yet been explored. In this study, we measure color preference and visual fatigue to evaluate LED task lighting for assembly operation. We conducted an experiment to obtain subjective responses to color preference and to measure visual fatigue under LED lighting. The participants were asked to assemble a gearbox model as a task under three different lighting conditions. As a result, lighting with high color temperature was rated with high visibility, fatigability, and low preference. On the other hand, critical fusion frequency, which indicates visual fatigue, was higher in lighting with low color temperature than in lighting with other conditions. This indicates that color preference as a subjective response discords from visual fatigue evaluated by biological information.