A shell catcher for use with hand-held firearms adjustably detachably mounts on a side of the firearm for receiving and retaining spent shells expelled by the firearm. The shell catcher has a base, which mounts on a side of the firearm and a collapsible flexible housing, which is detachably pivotally mounted on the mounting base. The housing is stretched on a rigid frame that moves between a closed position when the shells are received in the housing and an open position allowing unobstructed view of the gun chamber. The spent shells are removed from the housing by means of opening the bottom of the housing or by removing the housing from the base.