このころ

adverb, noun

at that time; in those days; then

Refers to a past period already mentioned or understood from context. Often used in narrative or reminiscing.

See also: その頃

• この頃ころはまだ子こ供どもだったので、何なにもわからなかった。

  At that time I was still a child, so I didn't understand anything.

• この頃ころ、彼かれは毎まい日にち遅おそくまで働はたらいていた。

  In those days, he worked late every day.