Cylindrical traverse grinding is often used for grinding slender workpieces with high accuracy. However, vibrations such as self-excited chatter frequently occur because of the low rigidity of the workpiece, and restrict finishing accuracy, productivity and wheel life. This paper presents a newly developed active rest for precision cylindrical traverse grinding. The vibration of the workpiece can be reduced by applying an additive viscous damping force from an electromagnetic rest without any contact between the rest and the workpiece. The active rest also controls the static deformation of the workpiece so as to realize a constant wheel depth of cut along the workpiece axis. First, the construction and mechanism of the active rest is presented, and its control is theoretically discussed. Then the effects on the suppression of vibrations are experimentally verified.