The high-voltage isolator (1) has a first electrical connecting element (2a) and a second electrical connecting element (2b) and an electrical insulating element (3) extends therebetween.  The end sections (4a, 4b) of the connecting elements (2a, 2b) are connected to the isolating element (3), wherein at least on one of the end sections (4a, 4b) there is a torus-shaped field control element (5).  At the end section (4a, 4b) featuring the field control element (5) there is a slot (6) extending in the perimeter direction of the end section (4a, 4b).  The field control element (5, 5a) and the associated end section (4a, 4b) are designed as a single piece.  Due to the provision of the slot (6), during longitudinal- and transverse contractions of the insulating element (2), any occurring tensile- and compression forces which act perpendicular to the longitudinal axis of the end section (4a, 4b), and also shear forces are generally prevented and a simultaneous retention of a good equalization in the region of the isolating path is achieved in the case of electrical fields occurring during operation.