A docking device is provided. A portable information device can be removably attached to a docking device. The docking device includes first and second connectors that are connected to connection terminals provided on the portable information device. The docking device further includes: a first substrate with the first connector mounted thereon; a second substrate with the second connector other than the first connector mounted on the first substrate mounted thereon; and a substrate connecting member that connects between the first and second connectors in a floating state that allows relative displacement.