To reduce or eliminate a variation in an increased output rotation from a booster mechanism.

In this gear type continuously variable transmission, the longitudinal shape of at least one of two side surfaces of each of the plurality of guide groove parts 4a of an offset member 4 which are opposed to each other and extend in the longitudinal direction of the guide groove part 4a has a curved shape which reduces the change of the swing angle of a crank 3 in only one direction more than in the case of a linear shape.