抄録
Nowadays the safety level of Japanese railways is very high, as 0.6 accidents happen per 10^6 km train-run and nearly zero on-board passengers are killed in a normal year. It is the fruits of technologies for safety and the efforts of people involved in railways. But unfortunately we had not a few serious accidents in the past. In this paper the author reports the outline of accident occurrences, countermeasures against them and safety progress in last 50 years in Japan, and explains the reorganization of the accident investigation body to newly established JTSB.