An exerciser includes a body and an adjustment wheel. The body has two flywheels and two foot support links. The two flywheels each have a sliding portion which radially connected thereto so as to guide the two foot support links to alternatively move along a supporting travel and a crossing travel to complete a closed pedal trajectory when the flywheels rotate. The timing adjustment wheel is pivotally connected to the body. The timing adjustment wheel has a first slider and a second slider, the first and second sliders are configured to move along the sliding portions of the flywheels. The foot support links drives the flywheel to rotate so that the first and second sliders move along the sliding portions to change the speeds and phase differences of the foot support links so as to meet the principles of ergonomics.