To easily install a conduit tube connector to a slab position by having a cylindrical anchorage device and an elbow type cylindrical rotary device provided to the cylindrical anchorage device in a detachable manner and capable of being rotated with the axis of the cylindrical anchorage device as the center.

A plastic cylindrical anchorage device 3 is held by a connector anchorage device 2 mounted to slab constructing forms. An elbow type cylindrical rotary device 4 of 90 is mounted thereto, The cylindrical anchorage device 3 and cylindrical rotary device 4 having a recessed groove 5 and a projected thread 6 respectively provided to the internal circumferential and external circumference along the circumferential direction are interlocked with each other in a detachable manner, and the projected thread 6 is slid in the recessed groove 5 in a joint state and is capable of being rotated within range of 0-360 degree. The cylindrical rotary device 4 is positioned at a specific rotational angle, a conduit tube joint socket 11 is connected to the other end to place concrete in a slab position, and after the completion of slab construction, the forms are removed. A connector 1 is easily installed to the slab position, and there is no damage in the joint end in the slab position. Durability of a conduit tube to be installed can be rapidly promoted.