In a structure in which electric appliances having a molded solid insulating object formed thereon are coupled to each other, air bubbles mixed into a connection interface at the time of a connectionwork, air bubbles generated on an interface due to deterioration of a flexible insulating object over a long period of time, and occurrence of partial electric discharge at a separation portion degrade the insulation function, and the present invention prevents such degradation. In this electric-appliance connecting device in which a first solid insulating object (4) and a second solid insulatingobject (9) obtained by respectively forming, on the peripheries of central conductors 3, 7, a molded solid insulating object are coupled to each other with a flexible insulating object (12) interposedtherebetween: a high voltage electrode (17) having an outer diameter larger than the outer diameter of the central conductor (3, 7) is disposed in the second solid insulating object (9); and a grounding electrode (16) having an inner diameter smaller than the inner diameter of an external grounding layer (10) of the second solid insulating object (9) but larger than the outer diameter of the highvoltage electrode (17) is disposed in the first solid insulating object (4). Electric field directions on the interface between the first solid insulating object (4) and the flexible insulating object (12) and on the interface between the second solid insulating object (9) and the flexible insulating object (12) are directions extending along the respective interfaces.