Shinzo Abe was given a specially-printed suit to protect him from radiation during the tour yesterday, on which he was accompanied by a large press pack.
But plant operator TEPCO, which has been lambasted internationally for what critics say is its hapless handling of the catastrophe at Fukushima, used the wrong Chinese character for part of the PM's name.
The first three of the four characters used to write his name were correct, however the final one represented the same sound but had a different meaning.
TEPCO has repeatedly come under fire for its approach to managing the aftermath of the disaster at Fukushima, with a government minister describing it as akin to someone playing "whack-a-mole".
The giant utility was pilloried on Twitter over the gaffe today.
User @YuriSakamoto tweeted "They can't get anything right, can they?"
"Isn't it a big deal that TEPCO didn't think twice about misspelling the name of the country's prime minister and had him wear it" said @PsychoQueen59, while @ShoHgo_chirpy said: "TEPCO cannot even check on something as trivial as this."
Earlier this month the premier, during Tokyo's successful pitch to host the 2020 Games, told Olympic chiefs: "Let me assure you, the situation is under control".
