A flexible tubular lining material impregnated with a thermosetting resin is folded and bound with binding members to provide a reduced width. Two elastic and rigid strip members are inserted into loop members attached to the lining material and are removably attached so as to sandwich the lining material. During pipeline lining work, the lining material to which the strip members have been attached is first inserted into a lateral pipe from a main pipe. The strip members are then removed from the lining material so that the lining material may remain inside the pipeline. The strip members are extracted from the pipeline, and the lining material is then made to expand via application of pressure from the inside. While kept in contact with the inner peripheral surface of the pipeline, the lining material is heated in order to cure the thermosetting resin thereof.