The invention relates to a method for detecting an electric arc in a photovoltaic facility, including the following steps: measuring (E6) voltage values at at least one location of the electric circuit of the photovoltaic facility; digitizing (E8) the measured voltage values in order to produce voltage data; forming (E11) a window of n recently digitized voltage data; calculating (E12) a test value associated with said window of n voltage data; analyzing (E13) a test vector that includes m test values associated with m recent windows generating a quantity originating from this analysis, which is representative of an electric arc risk; and comparing (E15) said resulting quantity with at least one threshold in order to derive therefrom the presence or absence of an electric arc within a photovoltaic facility.