Last year, the Oxford dictionaries announced 'post-truth' as its 2016 international Word of the Year. The specific proof, 'fake news' is coming up to a big social issue. The word 'post-truth' means the phenomenon that makes a formation of a public opinion that is affected much more by individual feeling and creed than objective truth. In 2016, the presidental election of America also affected by fake news enormously. Unlike the then current opinion that mostly supported Clinton, Trump-friendly fake news which spread through social network service brought about the complete opposite result to a general opinion of the time. 'Pope Francis amazes the world supporting Donald Trumph'and 'Hillary Clinton sells arms to IS' are examples of the above event. Fake news induce hostility and disgust people. For example, there were news including 'Russian minor was raped and murdered by refugees in Berlin'and 'Angela Merkel, Germany's chancellor, is the daughter of Adolf Hitler.' Then, why do these kinds of fake news appear? It is because of money. Various kinds of Internet news and portal sites get profits from advertisements requested to their homepage. This means that the number of click is their income. People cannot afford to deal with a lot of information in a limited time completely. So, this induces people to get more exciting information. This is the reason why the hits and reactions of punctual fake news are far superior than normal news. According to the analysis of 'Buzzfeed', the number of fake news sharing case was eight million and 70 thousand. This is larger than Facebook news sharing case of major media, which is seven million and 30 thousand cases. In other words, there are people who do not get proper information. Therefore, we have to be prudent when sharing information from the media, not to get the wrong one.