A spindle device includes a spindle shaft, a spindle housing, and a chuck portion as a rotating member. The chuck portion has, formed therein, a suctioning passage through which air suctioned from the outside flows. The spindle shaft has a first guide passage which guides air flowing through the suctioning passage to a clearance between the inner wall of the spindle housing defining a through hole in which the spindle shaft is inserted and the outer wall of the spindle shaft facing the inner wall, by way of the interior of the spindle shaft. The spindle housing has, formed therein, a second guide passage configured to guide the air guided to the clearance, to the outside.