Method for diagnosing the state of wear of an electrical switching device comprising: a) a preliminary learning phase for recording, over a predetermined number of manoeuvres, learning data (CD1, CD2) representative of at least two trend curves (CD1, CD2) of descriptors representative of predefined characteristics of an electrical signal during the life of said electrical device, b) a phase of storage of said learning data (CD1, CD2); c) a phase of loading of said learning data (CD1, CD2); d) an initialization phase for determining and storing initialization data comprising a specific reference curve of said electrical device to be checked; and e) a checking phase, which uses said learning data (CD1, CD2) and said initialization data, said checking phase comprising: - the measurement of a signal representative of an electrical quantity and the acquisition of a measurement curve of said electrical signal when said electrical device is switched off, - the determination of the value of local descriptors (DL1, DL2) of said measurement curve as a function of values of said measurement curve, of stored initialization data, and of first loaded learning data, at least one of said local descriptors (DL1, DL2) being a descriptor for which the sensitivity to temperature differences includes a deviation of less than 5% in value between -20°C and 80°C, and dependent on noteworthy points (20, 21) of said measurement curve, - the determination of the positioning of said local descriptor values (DL1, DL2) of the measurement curve with respect to second learning data (CD1, CD2), and - the determination of an overall state class as a function of said positioning values of the local descriptor values (DL1, DL2) and of the measurement curve with respect to said second learning data (CD1, CD2). a) a preliminary learning phase for recording, over a predetermined number of manoeuvres, learning data (CD1, CD2) representative of at least two trend curves (CD1, CD2) of descriptors representative of predefined characteristics of an electrical signal during the life of said electrical device, b) a phase of storage of said learning data (CD1, CD2); c) a phase of loading of said learning data (CD1, CD2); d) an initialization phase for determining and storing initialization data comprising a specific reference curve of said electrical device to be checked; and e) a checking phase, which uses said learning data (CD1, CD2) and said initialization data, said checking phase comprising: - the measurement of a signal representative of an electrical quantity and the acquisition of a measurement curve of said electrical signal when said electrical device is switched off, - the determination of the value of local descriptors (DL1, DL2) of said measurement curve as a function of values of said measurement curve, of stored initialization data, and of first loaded learning data, at least one of said local descriptors (DL1, DL2) being a descriptor for which the sensitivity to temperature differences includes a deviation of less than 5% in value between -20°C and 80°C, and dependent on noteworthy points (20, 21) of said measurement curve, - the determination of the positioning of said local descriptor values (DL1, DL2) of the measurement curve with respect to second learning data (CD1, CD2), and - the determination of an overall state class as a function of said positioning values of the local descriptor values (DL1, DL2) and of the measurement curve with respect to said second learning data (CD1, CD2). - the measurement of a signal representative of an electrical quantity and the acquisition of a measurement curve of said electrical signal when said electrical device is switched off, - the determination of the value of local descriptors (DL1, DL2) of said measurement curve as a function of values of said measurement curve, of stored initialization data, and of first loaded learning data, at least one of said local descriptors (DL1, DL2) being a descriptor for which the sensitivity to temperature differences includes a deviation of less than 5% in value between -20°C and 80°C, and dependent on noteworthy points (20, 21) of said measurement curve, - the determination of the positioning of said local descriptor values (DL1, DL2) of the measurement curve with respect to second learning data (CD1, CD2), and - the determination of an overall state class as a function of said positioning values of the local descriptor values (DL1, DL2) and of the measurement curve with respect to said second learning data (CD1, CD2).