An electric vehicle, comprising: a carrier for supporting a user; a free-wheel unit disposed at one end of the carrier, the free-wheel unit comprising a frame and a wheel, wherein the frame of the free-wheel unit is pivotally disposed on the carrier and is rotatable relative to the carrier, the wheel of the free-wheel unit is pivotally disposed on the frame of the free-wheel unit, and when the frame of the free-wheel unit is rotated, an angle between an axis of the wheel of the free-wheel unit and the carrier is changed; a foot-wheel unit disposed at the other end of the carrier, the foot-wheel unit comprising another frame and another wheel, wherein the frame of the foot-wheel unit is disposed on the carrier and is rotatable relative to the carrier, the wheel of the foot-wheel unit is pivotally disposed on the frame of the foot-wheel unit; a driving unit disposed at one of the free-wheel unit and the foot-wheel unit, and for providing a propulsive power to the electric vehicle; the electric vehicle being characterized in that: a first angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at one of the free-wheel unit and the carrier, wherein when the free-wheel unit is swung by a user, the first angle-detecting unit generates a first pulse wave; a micro processing unit signally connected to the driving unit and the first angle-detecting unit; and a voice prompting unit disposed at the carrier and electrically connected to the micro processing unit; a second angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at the foot-wheel unit, wherein when the foot-wheel unit is swung by the user relative to the carrier, the second angle-detecting unit generates a second pulse wave, and the micro processing unit determines whether the electric vehicle goes straight based on a generated number or a generated time period of the second pulse wave; wherein the micro processing unit determines whether to turn on the driving unit based on a generated number or a generated time period of the first pulse wave as long as the electric vehicle is going straight. a carrier for supporting a user; a free-wheel unit disposed at one end of the carrier, the free-wheel unit comprising a frame and a wheel, wherein the frame of the free-wheel unit is pivotally disposed on the carrier and is rotatable relative to the carrier, the wheel of the free-wheel unit is pivotally disposed on the frame of the free-wheel unit, and when the frame of the free-wheel unit is rotated, an angle between an axis of the wheel of the free-wheel unit and the carrier is changed; a foot-wheel unit disposed at the other end of the carrier, the foot-wheel unit comprising another frame and another wheel, wherein the frame of the foot-wheel unit is disposed on the carrier and is rotatable relative to the carrier, the wheel of the foot-wheel unit is pivotally disposed on the frame of the foot-wheel unit; a driving unit disposed at one of the free-wheel unit and the foot-wheel unit, and for providing a propulsive power to the electric vehicle; the electric vehicle being characterized in that: a first angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at one of the free-wheel unit and the carrier, wherein when the free-wheel unit is swung by a user, the first angle-detecting unit generates a first pulse wave; a micro processing unit signally connected to the driving unit and the first angle-detecting unit; and a voice prompting unit disposed at the carrier and electrically connected to the micro processing unit; a second angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at the foot-wheel unit, wherein when the foot-wheel unit is swung by the user relative to the carrier, the second angle-detecting unit generates a second pulse wave, and the micro processing unit determines whether the electric vehicle goes straight based on a generated number or a generated time period of the second pulse wave; wherein the micro processing unit determines whether to turn on the driving unit based on a generated number or a generated time period of the first pulse wave as long as the electric vehicle is going straight. a first angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at one of the free-wheel unit and the carrier, wherein when the free-wheel unit is swung by a user, the first angle-detecting unit generates a first pulse wave; a micro processing unit signally connected to the driving unit and the first angle-detecting unit; and a voice prompting unit disposed at the carrier and electrically connected to the micro processing unit; a second angle-detecting unit, that is a magnetic detector including an induced magnet and a Hall chip, disposed at the foot-wheel unit, wherein when the foot-wheel unit is swung by the user relative to the carrier, the second angle-detecting unit generates a second pulse wave, and the micro processing unit determines whether the electric vehicle goes straight based on a generated number or a generated time period of the second pulse wave; wherein the micro processing unit determines whether to turn on the driving unit based on a generated number or a generated time period of the first pulse wave as long as the electric vehicle is going straight.