Abe cited health reasons for his decision.
Dpa reports that there are five possible successors in his Liberal Democratic Party (LDP).
Number one is Deputy Prime Minister, Taro Aso.
The 79-year-old serves as Finance Minister, is expected to succeed Abe as interim premier.
Number two is Chief Cabinet Secretary Yoshihide Suga.
Since 2012 when Abe assumed power, Suga has been the government spokesperson.
Only Aso and Suga have retained their positions since the start of Abe’s administration.
Number three is Defence Minister, Taro Kono.
The 57-year-old served as Foreign Minister for over one year, before taking the current post.
Number four is former Defence Minister, Shigeru Ishiba.
The media has for long named the 63-year-old as a possible successor to Abe.
He served as the ruling party’s Secretary General and Chairman, Policy Research Council.
Number five is former Foreign Minister, Fumio Kishida, 63.
He held the position for more than four and a half years and currently chairs LDP’s Policy Research Council.
