A sensor system comprising: a plurality of sensors (30a, 30b, 30c) positioned along a line and measuring data indicating a passing state of a workpiece being conveyed upon the line, wherein the passing state indicates whether a workpiece is within the detection range of the sensor; a plurality of slave units (20a, 20b, 20c) respectively connected to the plurality of sensors (30a, 30b, 30c) and acquiring the data measured by the plurality of sensors (30a, 30b, 30c); and a master unit connected to the plurality of slave units (20a, 20b, 20c), wherein the master unit has: a storage part for storing the data in association with information which relates to the timing at which the data was measured, and a determination part for comparing the data transmitted from two or more of the plurality of slave units (20a, 20b, 20c) using the information which relates to the timing, and determining a change in state of the workpiece, wherein the data is time series data including rising waveforms or falling waveforms in accordance with the passing states of the workpiece being conveyed upon the line, and wherein the master unit further includes a mapping part for mapping the rising waveforms or the falling waveforms acquired by two or more of the plurality of slave units (20a, 20b, 20c) regarding the same workpiece on the basis of intervals of the rising waveforms or intervals of the falling waveforms included in the time series data acquired by the two or more slave units, wherein the mapping part performs mapping of rising waveforms or falling waveforms acquired by a first slave unit of the plurality of slave units (20a, 20b, 20c) and rising waveforms or falling waveforms acquired by a second slave unit of the plurality of slave units (20a, 20b, 20c) such that an average value of differences between the intervals of the rising waveforms or the intervals of the falling waveforms acquired by the first slave unit and the intervals of the rising waveforms or the intervals of the falling waveforms acquired by the second slave unit decreases; and wherein the mapping part performs mapping of rising waveforms or falling waveforms acquired by the first slave unit and rising waveforms or falling waveforms acquired by the second slave unit from combinations in which a number of items for calculating the average value is equal to or greater than a predetermined number. a plurality of sensors (30a, 30b, 30c) positioned along a line and measuring data indicating a passing state of a workpiece being conveyed upon the line, wherein the passing state indicates whether a workpiece is within the detection range of the sensor; a plurality of slave units (20a, 20b, 20c) respectively connected to the plurality of sensors (30a, 30b, 30c) and acquiring the data measured by the plurality of sensors (30a, 30b, 30c); and a master unit connected to the plurality of slave units (20a, 20b, 20c), wherein the master unit has: a storage part for storing the data in association with information which relates to the timing at which the data was measured, and a determination part for comparing the data transmitted from two or more of the plurality of slave units (20a, 20b, 20c) using the information which relates to the timing, and determining a change in state of the workpiece, a storage part for storing the data in association with information which relates to the timing at which the data was measured, and a determination part for comparing the data transmitted from two or more of the plurality of slave units (20a, 20b, 20c) using the information which relates to the timing, and determining a change in state of the workpiece, wherein the data is time series data including rising waveforms or falling waveforms in accordance with the passing states of the workpiece being conveyed upon the line, and wherein the master unit further includes a mapping part for mapping the rising waveforms or the falling waveforms acquired by two or more of the plurality of slave units (20a, 20b, 20c) regarding the same workpiece on the basis of intervals of the rising waveforms or intervals of the falling waveforms included in the time series data acquired by the two or more slave units, wherein the mapping part performs mapping of rising waveforms or falling waveforms acquired by a first slave unit of the plurality of slave units (20a, 20b, 20c) and rising waveforms or falling waveforms acquired by a second slave unit of the plurality of slave units (20a, 20b, 20c) such that an average value of differences between the intervals of the rising waveforms or the intervals of the falling waveforms acquired by the first slave unit and the intervals of the rising waveforms or the intervals of the falling waveforms acquired by the second slave unit decreases; and wherein the mapping part performs mapping of rising waveforms or falling waveforms acquired by the first slave unit and rising waveforms or falling waveforms acquired by the second slave unit from combinations in which a number of items for calculating the average value is equal to or greater than a predetermined number.