To provide a bearing unit, which can retain lubricating oil to contribute to cooling, and guide the lubricating oil out of the bearing unit, and further can improve the handleability of components in assembling.

A lubricating oil introduction member 11 includes a discharge port 31 of lubricating oil opened in opposition to a circumferential groove 28 of an inner ring 4 of a rolling bearing 3, and the introduction member 11 includes a recessed-shape part on its back surface. A lid member 30 to be fitted to the recessed-shape part is provided on the introduction member 11 in a fixed state. The lid member 30 includes an oil passage 30 for guiding the lubricating oil discharged to the outer diameter side through the discharge port 31 of the introduction member 11 out of the bearing unit.