An operator cab for heavy equipment is disclosed to prevent a sliding door mounted on the cab from rocking or rattling in X, Y, and Z-axis directions due to a shock or vibration applied to the cab in a state that the sliding door is fully opened or closed. The operator cab includes an outer sidewall having a doorway formed thereon; upper and lower rails provided on upper and lower portions of the outer sidewall; a sliding door being slid by upper and lower rollers engaged with the upper and lower rails; an upper stopper of an opened position, installed in the opened position of the outer sidewall, for being in contact with the upper roller when the sliding door is fully opened, to prevent the sliding door from rocking when the upper stopper becomes in contact with the upper roller; and a lower stopper of an opened position, installed in the opened position of the outer sidewall, for being in contact with the lower roller when the sliding door is fully opened, to prevent the sliding door from rocking when the lower stopper becomes in contact with the lower roller.