A stator unit includes a main circuit board parallel to an up-and-down direction, a sub circuit board at a right angle to the main circuit board, a magnetic sensor on the sub circuit board, and a housing including a sub circuit board space that is located adjacent to an inner space of the stator unit in which a can is disposed. The sub circuit board includes a first end connected to the main circuit board via a circuit board terminal and a second end located near the inner space in the sub circuit board space. The magnetic sensor is located closer to the inner space than the circuit board terminal is.