In the Japanese lower house, 314 out of 465 MPs voted for the current chief cabinet secretary on Wednesday. The House of Lords also voted for him by a majority.
The 71-year-old follows Shinzō Abe, who he had already replaced as party chairman on Monday, in the office of head of government. The previous incumbent announced at the end of August that he would be stepping down from his posts as prime minister and party chairman for health reasons. Abe was Prime Minister of Japan since December 2012. He had previously held this office from 2006 to 2007.