A lock system comprising a lock device (40, 140, 240, 340, 440, 540, 640) having a plurality of locks, and a multiple key (100, 200, 300, 400, 500) provided with lock/unlock functions for a plurality of locks, wherein the lock device (40, 140, 240, 340, 440, 540, 640) comprises: a casing (42, 53, 642, 653) having a first opening and a second opening; a cylinder lock that includes one end in which is formed a first keyhole into which the multiple key (100, 200, 300, 400, 500) is adapted to be inserted, and that is covered by the casing (42, 53, 642, 653) so that the first keyhole overlaps the first opening when viewed in a first axial direction of the first keyhole; and a shutter mechanism having a first shutter that is adapted to move between a closed position at which the first keyhole is blocked off and an open position at which the first keyhole is open, and a shutter lock (80, 280, 480) is adapted to operate the first shutter, the shutter lock (80, 280, 480) comprises: a rotor (70, 170); and a second keyhole (72, 74) that is covered by the casing (42, 53, 642, 653) so that the second keyhole (72, 74) overlaps the second opening when viewed in a second axial direction, and that is adapted to rotate in the circumferential direction of the second axis; and at least one first magnet is adapted to switch positions between a restricted position at which the rotation of the rotor (70, 170) is restricted, and a permitted position at which the rotation of the rotor (70, 170) is permitted, the rotor (70, 170) is adapted to rotate in a first state and a second state, in the first state the first shutter is positioned in the closed position, and in the second state the first shutter is positioned in the open position, the multiple key (100, 200, 300, 400, 500) comprises: a grip (101, 301, 401); a cylinder key that extends from the grip (101, 301, 401) and that is adapted to be inserted into the first keyhole and is adapted to lock and unlock the cylinder lock, characterized in that the rotor (70, 170) includes one end in which is formed the second keyhole (72, 74) into which the multiple key (100, 200, 300, 400, 500) is adapted to be inserted, and a magnet key (110, 210, 410) is provided around the proximal end of the cylinder key, the magnet key (110, 210, 410) has a base component in which a rotational axis is set in the direction in which the cylinder key extends and at least one second magnet provided to the base component, and with which the position of the first magnet can be switched by the magnetic force of the second magnet from the restricted position to the permitted position, the cylinder key is adapted to be inserted into the second keyhole (72, 74) of the rotor (70, 170), in a state in which the cylinder key has been inserted into the second keyhole (72, 74) of the rotor (70, 170), the magnet key (110, 210, 410) is adapted to switch the position of the first magnet of the shutter lock (80, 280, 480) from the restricted position to the permitted position, and in a state in which the cylinder key has been inserted into the second keyhole (72, 74) of the rotor (70, 170), the rotor (70, 170) is adapted to be rotated from the first state to the second state by turning the multiple key (100, 200, 300, 400, 500). a casing (42, 53, 642, 653) having a first opening and a second opening; a cylinder lock that includes one end in which is formed a first keyhole into which the multiple key (100, 200, 300, 400, 500) is adapted to be inserted, and that is covered by the casing (42, 53, 642, 653) so that the first keyhole overlaps the first opening when viewed in a first axial direction of the first keyhole; and a shutter mechanism having a first shutter that is adapted to move between a closed position at which the first keyhole is blocked off and an open position at which the first keyhole is open, and a shutter lock (80, 280, 480) is adapted to operate the first shutter, a rotor (70, 170); and a second keyhole (72, 74) that is covered by the casing (42, 53, 642, 653) so that the second keyhole (72, 74) overlaps the second opening when viewed in a second axial direction, and that is adapted to rotate in the circumferential direction of the second axis; and a grip (101, 301, 401); a cylinder key that extends from the grip (101, 301, 401) and that is adapted to be inserted into the first keyhole and is adapted to lock and unlock the cylinder lock, characterized in that the rotor (70, 170) includes one end in which is formed the second keyhole (72, 74) into which the multiple key (100, 200, 300, 400, 500) is adapted to be inserted, and a magnet key (110, 210, 410) is provided around the proximal end of the cylinder key, the magnet key (110, 210, 410) has a base component in which a rotational axis is set in the direction in which the cylinder key extends and at least one second magnet provided to the base component, and with which the position of the first magnet can be switched by the magnetic force of the second magnet from the restricted position to the permitted position,