A pair of tubular products (1a,1b) of polyarylene sulfide having end faces to be welded are welded to each other by heating the end faces by a hot plate (7) in no contact with the end faces to a surface temperature which is at least the melting heat-absorption peak temperature and at most 80 DEG C above the melting initiation temperature of the polyarylene sulfide, and abutting the end faces under a pressure of 50 - 1500 kPa when the end faces are at a surface temperature which is at least 10 DEG C above the melting initiation temperature and not exceeding the melting heat-absorption peak temperature of the polyarylene sulfide. As a result, a welded tubular structure having a weld with a small inside bead (9) but having a sufficiently large weld strength can be obtained with substantially no thermal degradation and at a good operating efficiency.