Abstract: A first substrate having a first electromagnetic noise sensor on its surface perpendicularly intersects with a second substrate having a second electromagnetic noise sensor on its surface, making up an integral structure. A first induced voltage value output from the first electromagnetic sensor at a position thereof directly before driving by a driving means is recorded, and a second induced voltage value output from the second electromagnetic noise sensor at a position thereof at a time of movement of the integral structure for only a predetermined distance by a driving means is recorded. Further, the first and second electromagnetic noise sensors are parallel connected at the position of movement, and a third induced voltage value output from a parallel connected electromagnetic noise sensor is also recorded. Based on the recorded first and second voltage values, an electromagnetic noise level in a vicinity of the integral substrate is determined.