A seat post with an offset of a bicycle includes a tube member. A clamp base is attached to the tube member. A lower clamp is disposed to the clamp base. An upper clamp is disposed to the lower clamp. An adjusting mechanism includes a first bolt member and a second bolt member. The first bolt member further includes a plurality of projected ribs at its outer wall. A spur wheel having a center hole is mounted on the outer wall ribs of the first bolt member and is rotatably disposed inside the clamp base. The second bolt member is disposed opposite to the first bolt member. By this arrangement, the upper clamp member and the lower clamp member are jointly fastened to the clamp base by the first and the second bolt members and an adjustment can be made easily by the help of the spur wheel.