A roller chain for a linear guideway comprises: a plurality of spacers each having two retaining portions and two links, each retaining portion is a hollow structure for holding the rollers. The retaining portions are formed at both sides of the rollers, one side of each of the retaining portions is opposite to the rollers, and another side doesn't contact any component, so that each two neighboring rollers are separated from each other completely. Each link is an elongated structure located at both ends of the rollers and employed to connect the spacers together. Hence, the impact energy caused when the spacer is impacted by the rollers will be converted into elastic energy, which prevents the indirect impact of two neighboring rollers caused by the spacer therebetween, thus effectively absorbing the impact force while substantially reducing the impact-caused noise.