The present invention provides a sensing device for obtaining information of a test sample using an electromagnetic wave including a frequency region within a frequency region of 30 GHz to 30 THz, the sensing device comprising an electromagnetic wave transmitting portion including a plurality of transmission portions (4a, 4b) for propagating electromagnetic waves and detection portions (3a, 3c) for receiving and detecting the electromagnetic waves from the plurality of transmission portions (4a, 4b), in which at least one of the plurality of transmission portions (4a, 4b) is constructed such that the test sample (5, 6) can be placed in a portion affected by an electromagnetic wave propagating therethrough.