An electric linear motion actuator comprising: a housing; a cylindrical outer ring member having a center axis, and mounted in the housing; a rotary shaft arranged on the center axis of the outer ring member, and configured to be rotated by an electric motor; a carrier including opposed first and second disks (41a,41b) configured to be rotatable about the rotary shaft, and a plurality of pillar members retaining the first and second disks (41a,41b) at a predetermined distance from each other; a plurality of planetary rollers mounted between an outer diameter surface of the rotary shaft and an inner diameter surface of the outer ring member, and rotatably supported by the carrier; wherein the outer ring member is formed, on the inner diameter surface of the outer ring member, with a helical rib, and each of the planetary rollers is formed, in an outer diameter surface of the planetary roller, with either circumferential grooves or a helical groove in which the helical rib is engaged; and a plurality of thrust roller and retainer assemblies each mounted between one of the planetary rollers and a surface of the first disk of the carrier that is opposed to the one of the planetary rollers such that thrust loads applied to the planetary rollers are supported by the respective thrust roller and retainer assemblies, wherein the electric linear motion actuator is configured such that when the rotary shaft rotates, due to frictional contact of the planetary rollers with the rotary shaft, the planetary rollers rotate about axes of the respective planetary rollers while revolving around the rotary shaft so that the outer ring member and the carrier axially linearly move relative to each other; characterized in that the electric linear motion actuator further comprises a common annular raceway disk common to all of the thrust roller and retainer assemblies, the common annular raceway disk being mounted between the thrust roller and retainer assemblies and a surface of the first disk that is opposed to the thrust roller and retainer assemblies. a housing; a cylindrical outer ring member having a center axis, and mounted in the housing; a rotary shaft arranged on the center axis of the outer ring member, and configured to be rotated by an electric motor; a carrier including opposed first and second disks (41a,41b) configured to be rotatable about the rotary shaft, and a plurality of pillar members retaining the first and second disks (41a,41b) at a predetermined distance from each other; a plurality of planetary rollers mounted between an outer diameter surface of the rotary shaft and an inner diameter surface of the outer ring member, and rotatably supported by the carrier; wherein the outer ring member is formed, on the inner diameter surface of the outer ring member, with a helical rib, and each of the planetary rollers is formed, in an outer diameter surface of the planetary roller, with either circumferential grooves or a helical groove in which the helical rib is engaged; and a plurality of thrust roller and retainer assemblies each mounted between one of the planetary rollers and a surface of the first disk of the carrier that is opposed to the one of the planetary rollers such that thrust loads applied to the planetary rollers are supported by the respective thrust roller and retainer assemblies, wherein the electric linear motion actuator is configured such that when the rotary shaft rotates, due to frictional contact of the planetary rollers with the rotary shaft, the planetary rollers rotate about axes of the respective planetary rollers while revolving around the rotary shaft so that the outer ring member and the carrier axially linearly move relative to each other; characterized in that the electric linear motion actuator further comprises a common annular raceway disk common to all of the thrust roller and retainer assemblies, the common annular raceway disk being mounted between the thrust roller and retainer assemblies and a surface of the first disk that is opposed to the thrust roller and retainer assemblies.