Prime minister have the authority to dissolve a parliament in Japan. He dares to use the authority when he think the chance that his desire would go well or he is drove by non-confidence. He is going to dissolve a parliament now because he is thinking it is chance to able to change the constitution as the rate of support for the ruling party is high. An administration of the Parliament of UK is 5 years and the dissolution is not permitted. They work hard eagerly during the administration without anxiety for the dissolution or election. As for Japan , the members of the Diet are always are afraid of dissolution and can’t work seriously. The dissolution is the worst system for nation and the Diet member but only prime minister.