That’s in contrast to the English version, which states the address as “Monkey Hill” (Sarugaoka), an address that doesn’t exist. At the time “Cherry Tree Hill” (Sakuragaoka) might have been correct. I pointed this out weeks ago, but MtGox somehow thinks there is no need to correct their error. They are probably too busy handling mountains of international bank withdrawals manually, or something.
Another way to find the address is to look at the Whois record for “mtgox.com”.
It says this:
Registrant Street: Round Cross Shibuya 5F
Registrant City: Shibuya
Registrant State/Province: Tokyo
Registrant Postal Code: 150-0002
Registrant Country: JP
And that was correct until recently (before the move to the building next door).
There even is a telephone number in that publicly available record.