An endoscope beam source apparatus which is connectable to an endoscope, the endoscope mounting a radiation optical system for radiating a beam onto a subject and an imaging optical system including an imaging device for imaging an image of the subject, the endoscope beam source apparatus comprising: a beam source adapted to emit radiation beam to be supplied to the endoscope; and a beam source control unit adapted to control emission beam intensity of the beam source according to a beam quantity specified value input therein, wherein the beam source control unit is adapted to specify the emission beam intensity by supplying a pulse-shaped beam source drive signal to the beam source, wherein the beam source control unit is adapted to perform electronic shutter control (i) according to a global shutter system, wherein the beam source control unit is adapted to specify the emission beam intensity of the beam source based on a combination of pulse number modulation control for changing the lighting time (Tb) per frame of the beam source to integer multiples of a fixed lighting cycle (Tc), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width within the lighting cycle (Tc), and pulse amplitude modulation control for changing the pulse amplitude, characterised in that the beam source control unit is further adapted to perform electronic shutter control, alternatively, (ii) according to a rolling shutter system, wherein the beam source control unit is adapted to specify the emission beam intensity of the beam source according to a combination of pulse density modulation control for changing the length of a lighting cycle (Td), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width (Te) within the lighting cycle, and pulse amplitude modulation control for changing the pulse amplitude. a beam source adapted to emit radiation beam to be supplied to the endoscope; and a beam source control unit adapted to control emission beam intensity of the beam source according to a beam quantity specified value input therein, wherein the beam source control unit is adapted to specify the emission beam intensity by supplying a pulse-shaped beam source drive signal to the beam source, (i) according to a global shutter system, wherein the beam source control unit is adapted to specify the emission beam intensity of the beam source based on a combination of pulse number modulation control for changing the lighting time (Tb) per frame of the beam source to integer multiples of a fixed lighting cycle (Tc), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width within the lighting cycle (Tc), and pulse amplitude modulation control for changing the pulse amplitude, characterised in that the beam source control unit is further adapted to perform electronic shutter control, alternatively, the beam source control unit is adapted to specify the emission beam intensity of the beam source based on a combination of pulse number modulation control for changing the lighting time (Tb) per frame of the beam source to integer multiples of a fixed lighting cycle (Tc), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width within the lighting cycle (Tc), and pulse amplitude modulation control for changing the pulse amplitude, characterised in that the beam source control unit is further adapted to perform electronic shutter control, alternatively, (ii) according to a rolling shutter system, wherein the beam source control unit is adapted to specify the emission beam intensity of the beam source according to a combination of pulse density modulation control for changing the length of a lighting cycle (Td), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width (Te) within the lighting cycle, and pulse amplitude modulation control for changing the pulse amplitude. the beam source control unit is adapted to specify the emission beam intensity of the beam source according to a combination of pulse density modulation control for changing the length of a lighting cycle (Td), wherein each lighting cycle comprises one pulse, pulse width modulation control for changing the pulse width (Te) within the lighting cycle, and pulse amplitude modulation control for changing the pulse amplitude.