A shield connector can easily suppress contact failure between terminal metal fittings due to vibration, and a connector connection structure can include the shield connector. In a large-diameter part in the natural state, a direction dimension passing through a tip of a protrusion is larger than a fastening direction dimension from an abutting part to a first clamping part in the shield case, a fastening member inserted into a fixed part is fastened, and the inner housing is thus hard to vibrate in the shield case. Therefore it is possible to suppress poor contact between a terminal fitting held by the inner housing and a mating terminal fitting. At this time, it is unnecessary to add a new process in order to suppress vibration of the inner housing, easily suppressing a contact failure between the terminal fittings.