A high-voltage insulator contains, in a coaxial arrangement: an insulating tube with an end in the form of a bearing ring, a hollow metal armature held on the bearing ring, an adhesive-bonding joint, which is provided between an adhesive-bonding area of the bearing ring and an adhesive-bonding area of the metal armature and is filled in a vacuum-tight manner with a cured adhesive layer, and a cavity, which is extended along the axis of the insulating tube and is radially delimited by the insulating tube and the metal armature. At least one predominantly radially guided adhesive channel is arranged between the cavity and the adhesive-bonding joint, which adhesive channel is sealed with cured adhesive and has a cross section which is sufficient for guiding uncured adhesive from the cavity into the adhesive-bonding joint prior to the formation of the cured adhesive layer.