A salient stimulus (a red target among green distractors) can automatically attract our attention. To examine neural representation of visual saliency, we trained monkeys to perform a visual search task in which a singleton target was different from distractors in color. We manipulated the degree of visual saliency of the target by independently changing "target-distractor color contrast" and "stimulus-background luminance contrast". For the estimation of the degree of visual saliency, we used saccade latency. Both contrasts can modulate saccade latency (when one of the contrasts larger, saccade latency became shorter). We found that these two contrasts differentially modulated neuronal activity in the posterior parietal cortex (PPC). Target-distractor color contrast modulated the late-period activity, whereas stimulus-background luminance contrast modulated the early-period activity. Thus,these results suggest that visual saliency derived from the different types of stimulus contrast is represented with different temporal dynamics in the activity of PPC neurons.