A motion analysis system includes first to N-th (N is an integer of 2 or more) sensor units which is attached to an object, an analysis unit which obtains a plurality of items of sampling data output from the sensor units, to analyze a motion of the object, a synchronization signal sending unit which transmits a first synchronization signal group including N first synchronization signals in order from the first to the N-th sensor unit, and transmits a second synchronization signal group including N second synchronization signals in order from the N-th to the first sensor unit, with respect to sensor unit, and a reference synchronization signal generation unit which generates a reference synchronization signal which is to be a reference with respect to the first to N-th sensor units, based on the first and second synchronization signal groups received by sensor unit.