A spindle motor includes a shaft including a core spindle member with a large and a small diameter portions and an encircling annulus member attached to the small diameter portion; a rotor hub attached to the large diameter portion; a bearing member; a radial bearing portion provided with first dynamic pressure creating grooves and formed between the outer peripheral surface of the encircling annulus member and the inner peripheral surface of the bearing member; a thrust bearing portion provided with second dynamic pressure creating grooves and formed between a lower end of the encircling annulus member and the bottom of the bearing member; a first opening formed at a radially inner side of the thrust bearing portion; a second opening formed at a radially outer side of the large diameter portion; and a communication hole continuously formed from the first opening to the second opening.