Grease which includes a base oil containing at least 50% by mass of a specific diester compound of a glycol with a branched carboxylic acid, and a specific diurea compound as a thickener. The grease is excellent in low-temperature performance and has low oil separation tendency. In particular, when used in a rotation transmission device having a built-in one-way clutch, the grease can provide satisfactory clutch engagement performance (intermeshing) at low temperatures and is less apt to cause oil separation under high centrifugal force.