A swivel exerciser includes a base frame, left and right handlebars, a plate on the base frame, a curved rail around the plate and fixedly secured onto the base frame, left and right stop members at both ends of the rail, pivotal left and right arms, left and right pedals on ends of the left and right arms respectively and being slidable on the rail, left and right projecting plates each at one side of the left or right arm and having a through hole, and an inverted U-shaped member. In a first exercise mode, the inverted U-shaped member has both ends inserted into the through holes of the pedals for interconnection so that both the left and right pedals may swing clockwise or counterclockwise. In a second exercise mode and after removing the inverted U-shaped member, either pedal may swing clockwise or counterclockwise independently.