Provided is a friction transmission device including an input raceway ring, a planetary rolling element that is disposed around a rotation axis of the input raceway ring and comes into contact with the input raceway ring; an output raceway ring that comes into contact with the planetary rolling element and is connected to an output shaft, and a first support raceway ring and a second support raceway ring that come into contact with the planetary rolling element. A quadrangle is formed by extension lines of normal vectors at contact points between the planetary rolling element and the respective raceway rings.