"With the country looking the other way, Japan’s authorities decided it was politically convenient to resume executions. To take a man’s life in this way is the politics of the gutter," Hiroka Shoji, an East Asia researcher at Amnesty International, was quoted as saying by the watchdog.
Kanda's execution is the 12th to be carried out under the current government since it took office in 2012.
"The government has a choice between continuing to take Japan down a regressive path, or ending executions and demonstrating it values human rights," said Shoji.
Shoji added that Japan was isolated and out of step with the vast majority of countries that have abandoned this "ultimate, cruel, inhuman and degrading" form of punishment.
According to Japanese government surveys, the death penalty in the country has an overwhelming public support of 80 percent.