We have developed a light-weight and large-area impact-ionization dust/debris detector, which we call IID. This detector consists of a gold plated metal target and two grids. Ratio of mass/volume of this parallel-plate type of detectors is simply proportional to the target area. Therefore, we can fulfill the requirements, i.e. “effective dust measurement with large aperture” and “light weighted to minimize the cost and payload” in future dust measurement in space. We can obtain information on mass and velocity of impacted particles by measuring the total charge and risetime of impact-generated plasma signals.