Abstract: In a continuous speed-shifting device in which a variable speed pulley mechanism and a planetary gear mechanism are combined with each other, respective cam mechanisms are provided on respective back sides of movable sheaves of variable speed pulleys of the variable speed pulley mechanism so as to move the sheaves toward and away from fixed sheaves of the variable speed pulleys, a linkage mechanism for linking both the cam mechanisms to each other is provided so that the diameters at which the belt is wound around both the pulleys are varied in a reverse direction to each other, the variable speed pulley mechanism is shifted in speed in such a manner that an output gear for supporting a pinion of the planetary gear mechanism is switched among a normal rotation state, a neutral state and a reverse rotation states with respect to a rotary shaft, the output gear is adjustable to the neutral state by a balance between the thrusts to the belt by both the pulleys, and the variable speed pulley mechanism serves as a