Abstract: Some implementations of the described invention provide an improved centerless grinding apparatus in which grinding is efficiently operated by reducing the idle time of the grinding wheel. While the described apparatus can comprise any suitable feature, in some cases, it includes a first regulating wheel and a second regulating wheel are axially aligned side by side. In some cases, a first grinding area is provided between the first regulating wheel and a first blade. In some cases, a second grinding area is provided between the second regulating wheel and a second blade. Additionally, in some cases, a grinding wheel is mounted on a grinding wheel Z-slide to be moved reciprocatively between the first grinding area and the second grinding area. In this way, grinding is efficiently operated by reducing the idle time of the grinding wheel.