A working machine comprising a perimeter-monitoring device, wherein the working machine comprises: a lower-part running body; an upper turning body mounted on the lower-part running body; an excavation attachment attached to a front-center part of the upper turning body; and a cab mounted on a front-left part of the upper turning body; wherein the perimeter-monitoring device comprises: a human presence determining means located on the upper turning body and configured to determine presence or absence of a human in each of a plurality of monitoring spaces (ZL, ZR, ZB) located around the upper turning body; an alarm means configured to be located in the cab of the working machine and to emit an alarm to an operator, a display part configured to be located in the cab; and an image creating means configured to create an image displayed on the display part by using at least one of a plurality of input images captured by a plurality of cameras (2L, 2R, 2B); wherein the image displayed on the display part is a virtual viewpoint image that is created by using the plurality of input images, that includes a computer generated, CG, image of the working machine at a center thereof, and that includes images of scenes at the back and side of the upper turning body around the CG image, wherein the plurality of monitoring spaces (ZL, ZR, ZB) include monitoring spaces at the back and side of the upper turning body, characterized in that when the human presence determining means has determined that a human exists at the side of the upper turning body, the alarm means emits an acoustic alarm from the side of a seat in the cab towards the seat, the side corresponding to the monitoring space (ZL, ZR, ZB) where the human exists, and wherein, when the human presence determining means has determined that a human exists at the back of the upper turning body, the alarm means emits an acoustic alarm from the back of the seat in the cab towards the seat. a lower-part running body; an upper turning body mounted on the lower-part running body; an excavation attachment attached to a front-center part of the upper turning body; and a cab mounted on a front-left part of the upper turning body; wherein the perimeter-monitoring device comprises: a human presence determining means located on the upper turning body and configured to determine presence or absence of a human in each of a plurality of monitoring spaces (ZL, ZR, ZB) located around the upper turning body; an alarm means configured to be located in the cab of the working machine and to emit an alarm to an operator, a display part configured to be located in the cab; and an image creating means configured to create an image displayed on the display part by using at least one of a plurality of input images captured by a plurality of cameras (2L, 2R, 2B); wherein the image displayed on the display part is a virtual viewpoint image that is created by using the plurality of input images, that includes a computer generated, CG, image of the working machine at a center thereof, and that includes images of scenes at the back and side of the upper turning body around the CG image, wherein the plurality of monitoring spaces (ZL, ZR, ZB) include monitoring spaces at the back and side of the upper turning body, characterized in that when the human presence determining means has determined that a human exists at the side of the upper turning body, the alarm means emits an acoustic alarm from the side of a seat in the cab towards the seat, the side corresponding to the monitoring space (ZL, ZR, ZB) where the human exists, and wherein, when the human presence determining means has determined that a human exists at the back of the upper turning body, the alarm means emits an acoustic alarm from the back of the seat in the cab towards the seat. a human presence determining means located on the upper turning body and configured to determine presence or absence of a human in each of a plurality of monitoring spaces (ZL, ZR, ZB) located around the upper turning body; an alarm means configured to be located in the cab of the working machine and to emit an alarm to an operator, a display part configured to be located in the cab; and an image creating means configured to create an image displayed on the display part by using at least one of a plurality of input images captured by a plurality of cameras (2L, 2R, 2B); wherein the image displayed on the display part is a virtual viewpoint image that is created by using the plurality of input images, that includes a computer generated, CG, image of the working machine at a center thereof, and that includes images of scenes at the back and side of the upper turning body around the CG image, wherein the plurality of monitoring spaces (ZL, ZR, ZB) include monitoring spaces at the back and side of the upper turning body, characterized in that when the human presence determining means has determined that a human exists at the side of the upper turning body, the alarm means emits an acoustic alarm from the side of a seat in the cab towards the seat, the side corresponding to the monitoring space (ZL, ZR, ZB) where the human exists, and wherein, when the human presence determining means has determined that a human exists at the back of the upper turning body, the alarm means emits an acoustic alarm from the back of the seat in the cab towards the seat.