A scanning endoscope system comprising: a light-guiding section that guides illuminating light emitted from a light source; an optical scanning section that includes at least one pair of piezoelectric elements arranged at positions to face each other across the light-guiding section, and is capable of swinging the light-guiding section so that a position in an object illuminated by the illuminating light forms a trajectory according to a predetermined scanning pattern by driving the at least one pair of piezoelectric elements; and a drive signal outputting section configured to output a first drive signal to one of the at least one pair of piezoelectric elements which are arranged along a predetermined axis direction (-X) in the optical scanning section and to output a second drive signal to the other of the at least one pair of piezoelectric elements, characterized in that the first drive signal has a first waveform with a first positive voltage value as a center, the first waveform having an amplitude value set so as not to fall below a first negative voltage value corresponding to a coercive electric field in the one piezoelectric element, the one piezoelectric element having been subjected to polarization processing in advance so as to have a predetermined polarization direction along the predetermined axis direction and having been formed so as to have a predetermined thickness in the polarization direction, the second drive signal has a second waveform with a second negative voltage value as a center, the second waveform having an amplitude value set so as not be larger than a second positive voltage value corresponding to a coercive electric field in the other piezoelectric element, the other piezoelectric element having been subjected to polarization processing in advance so as to have the same predetermined polarization and having been formed so as to have the same predetermined thickness in the polarization direction, wherein the first drive signal and the second drive signal have a same phase, and a value resulting from positive/negative reversal of a voltage value of one of the first positive voltage value and the second negative voltage value is equal to a voltage value of the other of the first positive voltage value and the second negative voltage value. a light-guiding section that guides illuminating light emitted from a light source; an optical scanning section that includes at least one pair of piezoelectric elements arranged at positions to face each other across the light-guiding section, and is capable of swinging the light-guiding section so that a position in an object illuminated by the illuminating light forms a trajectory according to a predetermined scanning pattern by driving the at least one pair of piezoelectric elements; and a drive signal outputting section configured to output a first drive signal to one of the at least one pair of piezoelectric elements which are arranged along a predetermined axis direction (-X) in the optical scanning section and to output a second drive signal to the other of the at least one pair of piezoelectric elements, characterized in that the first drive signal has a first waveform with a first positive voltage value as a center, the first waveform having an amplitude value set so as not to fall below a first negative voltage value corresponding to a coercive electric field in the one piezoelectric element, the one piezoelectric element having been subjected to polarization processing in advance so as to have a predetermined polarization direction along the predetermined axis direction and having been formed so as to have a predetermined thickness in the polarization direction, the second drive signal has a second waveform with a second negative voltage value as a center, the second waveform having an amplitude value set so as not be larger than a second positive voltage value corresponding to a coercive electric field in the other piezoelectric element, the other piezoelectric element having been subjected to polarization processing in advance so as to have the same predetermined polarization and having been formed so as to have the same predetermined thickness in the polarization direction, wherein the first drive signal and the second drive signal have a same phase, and a value resulting from positive/negative reversal of a voltage value of one of the first positive voltage value and the second negative voltage value is equal to a voltage value of the other of the first positive voltage value and the second negative voltage value.