Vehicle seat belt apparatus includes: a belt reel; a motor for driving the belt reel to take up a belt; a rotation detection section for detecting rotation of the belt reel; and a failure determination section for determining, on the basis of a detection signal output from the rotation detection section, whether or not the rotation detection section is currently in a failed state. The rotation detection section includes Hall ICs for generating first and second pulse signals that have characteristics such that temporal relationship between the first and second pulse signals is reversed in accordance with the rotating direction of the belt reel.