A bicycle seat device includes a seat post having a passage formed through a seat supporting base, a lower clamp member disposed on the seat supporting base and having an oblong hole aligned with the passage of the seat supporting base, a saddle having a space formed by a casing, an upper clamp member engaged into the space of the saddle and having a pathway and one or more recesses for receiving a pole. A fastener may clamp the saddle between the clamp members. The lower clamp member includes a curved surface for rotating relative to the seat supporting base to selected angular positions.