A quartz pipe joint of the present invention can be used in a connection of, for example, a quartz pipe and a quartz pipe, or a quartz pipe 7 and a synthetic resin tube. The quartz pipe joint A has a joint body having a tapered pressing face a cylindrical sealing member 33 having a tapered receiving face 33, a lock ring which can deform to increase its diameter and deform to reduce its diameter and which can be fitted into an annular groove of the quartz pipe and a nut. When the lock ring fitted into the annular groove and the sealing member fitted into the quartz pipe are clamped by threadedly connecting the nut to the joint body, the sealing member is deformed to reduce its diameter by the function of the pressing face and the receiving face, so as to closely contact with the outer peripheral face of the quartz pipe, thereby exerting sealing properties. The lock ring engages with a groove wall of the annular groove to prevent the quartz pipe from slipping off from the joint.