A hinge is connectable with two housing shells for permitting relative folding and unfolding of the housing shells, and includes a fixed seat, at least two rotating units, two lateral support plates and at least one synchronous driving unit. The rotating units are shiftable between an open state and a closed state. Each rotating unit includes a linking member fittingly and arcuately slidable on the fixed seat, a sliding member fittingly and arcuately slidable on the linking member, and a rotary bracket pivotably mounted on the fixed seat and inclinedly slidable on the sliding member. The lateral support plates are respectively mounted on the linking members. The synchronous driving unit includes two inboard pinions and two outboard pinions arranged laterally to mesh with bracket toothed portions of the rotary brackets to make synchronous rotation of the rotary brackets in opposite rotational directions.