According to an embodiment, a detection system includes a plurality of first sensors, a second sensor, a first calculator, and a second calculator. Each of the first sensors is configured to detect an elastic wave generated from a structure, and convert the elastic wave into a detection signal. The second sensor is configured to detect a noise propagating from surroundings, and convert the noise into a reference signal. The first calculator is configured to calculate a plurality of difference detection signals based on the respective detection signals and the reference signal. The second calculator is configured to calculate a position of a generation source of the elastic wave from the plurality of difference detection signals.