To provide an extremely economical and simple straw aligning machine capable of aligning straws composed of a lightweight plastic tube, manufactured by obliquely cutting a pair in the center, and mutually turning in the inverse direction, at a high speed in the same direction without relying on mechanical operation.

This straw aligning machine is provided with a pair of stairs-shaped slits having a gentle inclination in a cylinder, and applies a constant turning angle of 90° or 180° to the straws by a groove surface for realizing a constant falling speed of a high speed by frequently repeating a collision with the groove surface by natural falling motion.