Used to introduce something the speaker finds surprising; means 'surprisingly' or 'astonishingly,' emphasizing surprise or unexpectedness.
驚いたことに、彼は一度も遅刻したことがないと言った。
Surprisingly, he said he has never been late even once.
驚いたことに、古い写真の中に自分の祖父の若い頃の姿を見つけた。
Amazingly, I found a picture of my grandfather when he was young in an old photo album.
調査の結果、驚いたことに多くの人がその問題を知らなかった。
As a result of the survey, surprisingly many people did not know about that issue.