A jack connector includes pairs of jack signal contacts and jack ground contacts arranged alternately, and a plug connector includes pairs of plug signal contacts and plug ground contacts arranged alternately. Respective contacts of each pair of jack signal contacts come into contact with respective contacts of each pair of plug signal contacts, and each jack ground contact comes into contact with each plug ground contact. In a first contact structure, each jack ground contact comes into contact with each plug ground contact at a first position, and in a second contact structure each jack ground contact comes into contact with each plug ground contact at a second position apart from the first position along an extending direction of the plug ground contact.