A safety joint including: a nozzle side member with a flow path formed inside, a shutoff valve of the nozzle side member opens when the nozzle side member is connected to a filling apparatus side member; and the filling apparatus side member with a cylindrical shape, a flow path in communication with the flow path of the nozzle side member is formed when the filling apparatus side member is connected to the nozzle side member; and when the nozzle side member is disconnected from the filling apparatus side member, the flow paths (1A, 21A) of the nozzle side member and the filling apparatus side member are shut off, wherein said filling apparatus side member has an opening that communicates with the flow path of the filling apparatus side member and extends orthogonally to the flow path of the filling apparatus side member; when the nozzle side member and the filling apparatus side member are connected, a protruding portion of the nozzle side member is inserted into the opening on the filling apparatus side; and a filling apparatus side member flow path blocking mechanism is provided to instantly close the flow path of the filling apparatus side member at an initial stage when the nozzle side member is disconnected from the filling apparatus side member, wherein said filling apparatus side member flow path blocking mechanism includes a plug member slidably inserted into the opening of the filling apparatus side member; the plug member is connected to the protruding portion of the nozzle side member; a sealing material (S1, S2) is arranged at the opening of the filling apparatus side member to prevent a high-pressure gas from leaking from boundaries between an outer peripheral surfaces of the protruding portion of the nozzle side member as well as the plug member and an inner peripheral surface of the opening, characterized in that it comprises a mechanism for disconnecting the plug member from the protruding portion of the nozzle side member when the nozzle side member is disconnected from the filling apparatus side member, wherein said mechanism includes: a groove formed in the protruding portion of the nozzle side member; an opening portion formed on the plug member; a ball fitted in the groove formed in the protruding portion and the opening portion formed on the plug member; an enlarged diameter portion at the opening portion of the filling apparatus side member; a flange portion at an end of the plug member; and an end face of a stopper member provided on the filling apparatus side member. the filling apparatus side member with a cylindrical shape, a flow path in communication with the flow path of the nozzle side member is formed when the filling apparatus side member is connected to the nozzle side member; and when the nozzle side member is disconnected from the filling apparatus side member, the flow paths (1A, 21A) of the nozzle side member and the filling apparatus side member are shut off, wherein said filling apparatus side member has an opening that communicates with the flow path of the filling apparatus side member and extends orthogonally to the flow path of the filling apparatus side member; when the nozzle side member and the filling apparatus side member are connected, a protruding portion of the nozzle side member is inserted into the opening on the filling apparatus side; and a filling apparatus side member flow path blocking mechanism is provided to instantly close the flow path of the filling apparatus side member at an initial stage when the nozzle side member is disconnected from the filling apparatus side member, wherein said filling apparatus side member flow path blocking mechanism includes a plug member slidably inserted into the opening of the filling apparatus side member; the plug member is connected to the protruding portion of the nozzle side member; a sealing material (S1, S2) is arranged at the opening of the filling apparatus side member to prevent a high-pressure gas from leaking from boundaries between an outer peripheral surfaces of the protruding portion of the nozzle side member as well as the plug member and an inner peripheral surface of the opening, characterized in that it comprises a mechanism for disconnecting the plug member from the protruding portion of the nozzle side member when the nozzle side member is disconnected from the filling apparatus side member, wherein said mechanism includes: a groove formed in the protruding portion of the nozzle side member; an opening portion formed on the plug member; a ball fitted in the groove formed in the protruding portion and the opening portion formed on the plug member; an enlarged diameter portion at the opening portion of the filling apparatus side member; a flange portion at an end of the plug member; and an end face of a stopper member provided on the filling apparatus side member.