A sealing device 12b of a hub unit bearing O has a first slinger 16 fixed to an inner ring 5, a second slinger 17 fixed to an outer ring 1, and a sealing portion 18 which is fixed to the first slinger 16 and is slide-contacted with the second slinger 17. A magnetic encoder 20 is fixed to the first slinger 16. The magnetic encoder 20 and the sealing portion 18 are bond-fixed to the first slinger 16 with the same adhesive agent.