Abstract: An oscillation generating apparatus which has an oscillating shaft supported rotatable about an axis thereof, at least a cam follower attached eccentric to the oscillating shaft, at least a pair of drive shafts disposed parallel to the oscillating shaft and adapted to be connected to drive means to be rotated thereby; and at least a pair of cams attached to the pair of drive shafts for rotational movement therewith and kept in sliding contact with the cam follower, shape and location of the cams being so determined that at least one of the cams gives thrust force to the cam follower at any rotational angle of the oscillating shaft as the drive shafts are bieng rotated, whereby rotational movement of the drive shafts being converted to a back-and-forth rotational movement of the oscillating shaft. With the apparatus, a high rotational speed of the drive shaft can be correctly converted to a back-and-forth rotational movement of the oscillating shaft.