A projector comprising: a laser light source to supply a laser light according to an input image signal; a scanning section to perform scanning with the laser light supplied from the laser light source; a beam splitter to divide the laser light, scanned by the scanning section, into a first direction and a second direction to output the divided pieces of the laser light from the projector; a light receiving sensor to receive a reflected light of a first laser light output into the first direction by the beam splitter; characterized in that it further comprises: a determination section to specify a reflection position of the reflected light received by the light receiving sensor based on a horizontal synchronizing signal and a pixel clock signal of the image signal, and to determine an amplification quantity of an intensity of the reflected light reflected at the specified reflection position to be received by the light receiving sensor; an amplification section to amplify the intensity of the reflected light received by the light receiving sensor according to the amplification quantity determined by the determination section; an identification section to identify an external obstacle when the intensity of the reflected light amplified by the amplification section exceeds a predetermined threshold value; and a calculation section to calculate position information of the external obstacle based on a timing of identification of the external obstacle by the identification section, the horizontal synchronizing signal, and the pixel clock signal. a laser light source to supply a laser light according to an input image signal; a scanning section to perform scanning with the laser light supplied from the laser light source; a beam splitter to divide the laser light, scanned by the scanning section, into a first direction and a second direction to output the divided pieces of the laser light from the projector; a light receiving sensor to receive a reflected light of a first laser light output into the first direction by the beam splitter; characterized in that it further comprises: a determination section to specify a reflection position of the reflected light received by the light receiving sensor based on a horizontal synchronizing signal and a pixel clock signal of the image signal, and to determine an amplification quantity of an intensity of the reflected light reflected at the specified reflection position to be received by the light receiving sensor; an amplification section to amplify the intensity of the reflected light received by the light receiving sensor according to the amplification quantity determined by the determination section; an identification section to identify an external obstacle when the intensity of the reflected light amplified by the amplification section exceeds a predetermined threshold value; and a calculation section to calculate position information of the external obstacle based on a timing of identification of the external obstacle by the identification section, the horizontal synchronizing signal, and the pixel clock signal. a determination section to specify a reflection position of the reflected light received by the light receiving sensor based on a horizontal synchronizing signal and a pixel clock signal of the image signal, and to determine an amplification quantity of an intensity of the reflected light reflected at the specified reflection position to be received by the light receiving sensor; an amplification section to amplify the intensity of the reflected light received by the light receiving sensor according to the amplification quantity determined by the determination section; an identification section to identify an external obstacle when the intensity of the reflected light amplified by the amplification section exceeds a predetermined threshold value; and a calculation section to calculate position information of the external obstacle based on a timing of identification of the external obstacle by the identification section, the horizontal synchronizing signal, and the pixel clock signal.