The invention relates to an electric connection case (1), which can be used to improve the production efficiency, inhibit the production costs, realize the reduction of the part number and the assembly time, and save the installation space. The electric connection case comprises a bottom case (2) and a top case (3). The bottom case (2) is adjacent to a member installation part (2A), and can be used to hold a terminal installation part (45) of a first additional terminal. A pair of side wall parts (41) and a bottom wall part (43) can be used to form a part of a peripheral wall used for encircling the first additional terminal. The top case (3) is formed integratedly, and is adjacent to a member accommodation part (3A), and is used to hold a cylinder part (55) of a second additional terminal. An upper wall part (53) can be used to form the other part of the peripheral wall around the first additional terminal. By combining the bottom case (2) and the top case (3), the peripheral wall can be formed by the pair of side wall parts (41), a bottom wall part(43), and the upper wall part (53), and a direction of an opening part (4) of the peripheral wall is intersected with a direction of an opening part of the cylinder part (55).