A light source apparatus comprising: a first light source that emits light including a first wavelength band and a second wavelength band; a second light source that emits light in a third wavelength band, the third wavelength band being different from the light in the first and second wavelength bands; an optical filter section including a transmission section that transmits light in the first wavelength band, but blocks light in the second wavelength band; an optical path joining section that reflects the light in the third wavelength band emitted from the second light source to join an optical path of the light in the third wavelength band to an optical path of the light emitted from the first light source; an illumination mode selection section for selecting one of first to third illumination modes; and an optical filter drive section that if the first illumination mode is selected in the illumination mode selection section, drives the optical filter section so that the transmission section is retracted from the optical path of the light emitted from the first light source, if the second illumination mode is selected, drives the optical filter section so that the transmission section is continuously inserted in the optical path of the light emitted from the first light source, and if the third illumination mode is selected, drives the optical filter section so that the transmission section is intermittently inserted in the optical path of the light emitted from the first light source, wherein the light source apparatus further comprises a light amount control section that, if the second illumination mode or the third illumination mode is selected in the illumination mode selection section, lights up the second light source to make light from the second light source enter the optical path of the light emitted from the first light source, and controls a light amount of at least one of the first light source and the second light source so that a light amount ratio between an amount of light in the first wavelength band emitted from the first light source and passed through the transmission section and an amount of the light in the third wavelength band emitted from the second light source is a predetermined ratio. a first light source that emits light including a first wavelength band and a second wavelength band; a second light source that emits light in a third wavelength band, the third wavelength band being different from the light in the first and second wavelength bands; an optical filter section including a transmission section that transmits light in the first wavelength band, but blocks light in the second wavelength band; an optical path joining section that reflects the light in the third wavelength band emitted from the second light source to join an optical path of the light in the third wavelength band to an optical path of the light emitted from the first light source; an illumination mode selection section for selecting one of first to third illumination modes; and an optical filter drive section that if the first illumination mode is selected in the illumination mode selection section, drives the optical filter section so that the transmission section is retracted from the optical path of the light emitted from the first light source, if the second illumination mode is selected, drives the optical filter section so that the transmission section is continuously inserted in the optical path of the light emitted from the first light source, and if the third illumination mode is selected, drives the optical filter section so that the transmission section is intermittently inserted in the optical path of the light emitted from the first light source, wherein the light source apparatus further comprises a light amount control section that, if the second illumination mode or the third illumination mode is selected in the illumination mode selection section, lights up the second light source to make light from the second light source enter the optical path of the light emitted from the first light source, and controls a light amount of at least one of the first light source and the second light source so that a light amount ratio between an amount of light in the first wavelength band emitted from the first light source and passed through the transmission section and an amount of the light in the third wavelength band emitted from the second light source is a predetermined ratio.