We know very little about the interactions between cutaneous sensations because of the difficulties to make clear whether the interaction is caused in central nerve system or variance peripheral receptor sensitivity by multiple stimuli. Now, we conducted an experiment to examine whether the thermal sensation bias the tactile hardness perception without actual thermal difference in peripheral receptors by using illusory referred thermal sensation: when the index and ring fingers were placed on warm (cold) material and the middle finger was placed on a neutral thermal material, participant feel warm (cold) by all three fingers. The hardness of comparison stimulus was varied according to double stair case method. Seven participants conducted two-alternative-forced-choice task on perceived hardness on middle finger. The result shows that participant feel sample harder under cold condition than that under the warm condition. This phenomenon implies that that illusory thermal experience induces tactile illusion; warm (cold) material is felt soft (hard).