Concessive conjunction used to acknowledge a preceding statement while introducing a contrasting or qualifying point. Often used in both spoken and written Japanese.
彼
は
とても
忙
しい
。
と
は
言
う
もの
の
、
週
末
に
は
必
ず
家
族
と
過
ごし
て
いる
。
He is very busy. Having said that, he always spends weekends with his family.