Provided is an electrical connection cassette with which it is possible to freely expand a device and add functions in accordance with the size of free space. An electrical connection cassette is provided with: a circuit board; and first connection terminals and second connection terminals mounted on the circuit board and having terminal shapes that can be engaged with each other. In a state with a terminal connection direction oriented in a predetermined direction with respect to the circuit board, the first connection terminals are disposed on the side of one main surface of the circuit board, and in a state with a terminal connection direction oriented in a direction parallel to the predetermined direction, the second connection terminals are disposed near the other main surface of the circuit board.