A pitch cone angle measurement method according to the present invention comprises: causing a contacting portion 51 having a predetermined shape and size to come into contact with protruding ridge portions 41 which are constituents of a rotational power transmitting element 40; causing a contacting portion 52 to come into contact with the protruding ridge portions 41 in a position that is spaced apart from a position Pe1 of contact between the protruding ridge portions 41 and the contacting portion 51 in the first contacting step, by a predetermined radial distance d in a direction perpendicular to the direction of an axis of rotation L of the rotational power transmitting element 40; measuring a distance S in the direction of the axis of rotation L between the position Pe1 of contact between the contacting portion 51 and the protruding ridge portions 41 and a position Pe2 of contact between the contacting portion 52 and the protruding ridge portions 41; and calculating, on the basis of the distance S in the
