A joint structure includes a drive side insertion portion of a drive shaft, a driven side insertion portion of a driven shaft, and a coupling. The coupling includes a drive shaft insertion bore, which receives the drive side insertion portion, and a driven shaft insertion bore, which receives the driven side insertion portion. The drive shaft insertion bore includes a wall surface that engages the drive side insertion portion. The driven shaft insertion bore includes a wall surface that engages the driven side insertion portion. A drive side clearance in the drive shaft insertion bore allows the drive side insertion portion to move in the radial direction. A driven side clearance in the driven shaft insertion bore allows the driven side insertion portion to move in the radial direction.