A thigh exerciser includes a U-shaped frame having a space formed between two levers, a retaining member coupled between the levers for connecting and retaining the levers of the frame together, and a spring biasing member having two arms engaged with the levers and secured to the levers respectively for securing the spring biasing member to the levers of the frame. The frame includes a projection extended from each of the levers for engaging with the arms and for securing the arms of the spring biasing member to the levers of the frame. The spring biasing member includes a channel formed in each of the arms for slidably and adjustably engaging with the projection of the lever.