noun
notary office
A public office where a notary public (公証人) performs official authentications, certifications, and notarizations.
遺言書の認証を受けるために公証人役場へ行った。
I went to the notary office to have my will authenticated.
公証人 is the notary public (the person), while 公証人役場 is the office where the notary works.
Compound of 公証人 (notary public) + 役場 (public office).