A step exerciser has a base, a pedal element pivotally mounted on the base, and having a first female hollow shank pivotally mounted on the base, two pedals mounted on two opposed sides of and pivoted relative to the first female hollow shank, an interconnection element connected between the pedals and the first female hollow shank, and a damping element provided on the pedal element. Hence, the step exerciser can provide a user with various exercise effects.