In a grinding machine, a bed 10 has secured thereon a work head 11 which rotatably supports a work spindle 12 for supporting a workpiece W and mounts thereon a slide base 15 reciprocatively movable in a Z-direction parallel to the axis of the work spindle, and a wheel head 16 carrying a rotating grinding wheel 17 is reciprocatively movable on the slide base in an X-direction intersecting with the Z-direction. A measuring device 25 for measuring the dimension of the workpiece ground with the grinding wheel is mounted on an extreme end of a support arm 21 secured to the slide base to extend in the X-direction, through an actuator device 23 which is operable for moving the measuring device between a measuring position for engagement with the workpiece and a parked position for disengagement therefrom. The support arm passes over the workpiece, or passes through a space between the bed and the workpiece, or passes through the inside of the bed.