Metaphor comprehension needs a categorization process. The categorization process includes two different functions to the vehicle of metaphor: one is the activation of metaphor-relevant meaning, and the other is the suppression of metaphor-irrelevant meaning. Some previous studies showed that the conventionality of the vehicle and the aptness of the metaphor affect whether the categorization process happens. But they did not clarify whether these factors affect the activation and the suppression. In this point, our past study showed the evidence of the effect of the conventionality and the aptness on the activation of metaphor-relevant meaning. And in this study, we investigated the effect of these factors on the suppression of metaphor-irrelevant meaning. One experiment that consisted of a metaphor-priming task and a meaningfulness decision task showed that after metaphor comprehension, the vehicle suppress the metaphor-irrelevant meaning regardless both of the conventionality of the vehicle and the aptness of the metaphor.