| 1954 |
Formation of a working group for the foundation of an institute for nuclear study. |
| 1955 |
The Institute of Nuclear Study (INS) was established. |
| 1957-09 |
Sep：FF cyclotron was completed. |
| 1958-05 |
May：FM cyclotron was completed. |
| 1958-06 |
Jun：The first experiment with the FF cyclotron took place. |
| 1960-10 |
Oct：The first experiment with the FM cyclotron took place. |
| 1961-12 |
Dec：The Electron Synchrotron (ES) accelerated an electron beam to 750 MeV. |
| 1963-04 |
Apr：The first experiment with the ES took place. |
| 1964-04 |
Apr：Formation of a working group for the foundation of a new research institute for elementary particle physics. |
| 1966-03 |
Mar：The ES produced a 1.3 GeV beam. |
| 1971-04 |
Apr：National Laboratory for High Energy Physics (KEK) was established. |
| 1976-03 |
Mar：The proton synchrotron (PS) produced an 8 GeV beam as designed. |
| 1976-12 |
Dec：The PS achieved 12 GeV. |
| 1977-05 |
May：The first PS experiment took place. |
| 1977-12 |
Dec：Experiments with the SF cyclotron began. |
| 1978 |
The Booster Synchrotron Utilization Facility and a Photon Factory (PF) were founded. |
| 1978 |
The Meson Science Facility was established. |
| 1980-07 |
Jul：Experiments in the Booster Synchrotron Utilization Facility began. |
| 1982-03 |
Mar：The PF succeeded in storing a 2.5 GeV electron beam. |
| 1983-06 |
Jun：PF Experiments began. |
| 1984-07 |
Jul：The TRISTAN Accumulation Ring (AR) accelerated an electron beam to 6.5 GeV. |
| 1985-10 |
Oct：The AR accelerated a positron beam to 5 GeV. |
| 1986-11 |
Nov：The TRISTAN Main Ring (MR) accelerated both electron and positron beams to 25.5 GeV. |
| 1987-05 |
May：TRISTAN experiments began. |
| 1988-04 |
Apr：The Meson Science Facility was reorganized as a Laboratory (MSL). |
| 1988-11 |
Nov：The MR energy was upgraded to 30 GeV with the help of superconducting accelerating cavities. |
| 1989-09 |
Sep：First electron cooling by TARNII. |
| 1993-03 |
Mar：Isotope Separator On-Line (ISOL) was completed. |
| 1994-06 |
Jun：KEKB B-factory construction began. |
| 1995-12 |
Dec：TRISTAN experiments finished. |
| 1997 |
The High Energy Accelerator Research Organization was established. |
| 1998 |
First beam storage at KEKB (KEK B-factory) ring. |
| 1999-04 |
The Department of Particle and Nuclear Science was founded in the Graduate University for Advanced Studies. |
| 1999-05 |
The Long-baseline Neutrino Oscillation experiment (K2K) began. |
| 1999-06 |
The Belle experiment at the KEK B-factory began operation. |
| 2000 |
Tanashi Branch closed |
| 2001 |
Construction of High Intensity Proton Accelerators (J-PARC) started |
| 2004-04 |
Became the Inter-University Research Institute Corporation High Energy Accelerator Research Organization. |
| 2004-11 |
K2K experiment ended |
| 2005-04 |
Tokai Campus was opened. |
| 2005-12 |
Experiments at PS ended. |
| 2006-02 |
J-PARC Center was established. |
| 2006-03 |
Experiments at BSF ended. |
| 2007-01 |
181MeV proton beam at J-PARC Linac |
| 2007-10 |
3 GeV proton beam at J-PARC Rapid Cycling Synchrotron (RCS) |
| 2008-10 |
Prof. Makoto Kobayashi, former director of IPNS, won the 2008 Nobel Prize in Physics. |
| 2009-03 |
J-PARC construction was completed. |
| 2010-06 |
The Belle experiment ended |
| 2011 |
Construction of the SuperKEKB started |
| 2016 |
Phase 1 operation of the SuperKEKB started |
