To provide a bearing unit with a sensor improved in disassembling performance thereof, while restricted in deterioration of the disassembling performance even in the case of a small diameter.
A pulser ring 3 has two layers of magnetism generating layers 8a and 8b formed with a plurality of magnetism generating parts in the circumferential direction with an equal pitch. These magnetism generating layers 8a and 8b are overlapped with each other in the radial direction so that opposite magnetic poles face to each other. The sensor device 2 is provided with a magnetic sensor 12 opposite to the pulser ring 3, a magnetism generating member 21 arranged opposite to the magnetic sensor 12 through the pulser ring 3 to generate magnetism, and a magnetism focusing member 22 for focusing magnetic flux density of the magnetism from the magnetism generating member 21 and the pulser ring 3 to lead it to the magnetic sensor 12.
ISHII HIDEAKI
Einosuke Kishimoto
Akira Watanabe
Kiyosue Yasuko