To provide a grinding device with a simple configuration that achieves the homogenous ground surface in the whole machining area of a workpiece.

The grinding device includes: a reciprocatingly moving mechanism (a motor) that reciprocatingly moves a grinding wheel (a honing head), rotationally driven by a rotational-driving mechanism (a motor), along a rotary shaft of the rotational-driving mechanism; and a rotational-speed control means (a control unit) that executes deceleration control of a rotational speed Vθ of the grinding wheel according to changes in moving speed Vh of the grinding wheel near the turning point of the grinding wheel to be reciprocatingly moved. The rotational speed of the grinding wheel is controlled to be decelerated to the rotational speed (the peripheral speed) matching the moving speed of the grinding wheel. When the moving speed becomes zero, the rotational speed is also made zero. Therefore, the relationship between the reciprocatingly moving speed and the rotational speed (the peripheral speed) of the grinding wheel is completely synchronized. By this way, the crossing angle of a crosshatch line is made constant in the whole machining area of a workpiece.