A rolling bearing device includes a rolling bearing; and a spacer provided adjacent to one side of the rolling bearing in an axial direction and having a grease reservoir and a flow path, the grease reservoir being in a form of a groove, extending along a circumferential direction, and having grease reserved in the grease reservoir, and the flow path providing communication between the grease reservoir and an inner part of the rolling bearing. The spacer includes an annular wall surface that defines an inner periphery of the grease reservoir. An end of the annular wall surface on a side of the rolling bearing in the axial direction of the grease reservoir is continuous with an opposed end face of the spacer that is opposed to the rolling bearing. An entire area of the annular wall surface is constituted by a flat surface.