To provide a simplified stopper for a sliding door, simply stopping a sliding door at the fully opening position without trouble at need, and simply releasing the closing regulated state without the smallest strain in closing the sliding door once stopped sliding.

This simplified stopper A for a sliding door is formed by removably connecting an arm 15 having a hook part 15a rotatably engaged with a grip-type handle 13 to a magnet holder 25 holding a magnet 20. In fully opening the sliding door D, when the magnet 20 is located opposite to a vertical frame material 10 at the door end side of an iron-made door frame W by rotation, the magnet is magnetically attracted to the vertical frame material to regulate the closing operation of the sliding door to keep the sliding door in the fully opening position.