IMAGE ACQUISITION DEVICE FOR WORK MACHINE, INFORMATION MANAGEMENT SYSTEM, INFORMATION TERMINAL, AND IMAGE ACQUISITION PROGRAM FOR WORK MACHINE

An excavator 100 includes an imaging device 40 that captures an image in a periphery of the excavator 100, and a controller 30. The controller 30 causes the imaging device 40 to capture the image, when an imaging range of the imaging device 40 includes a predetermined subject region designated in advance in the periphery of the excavator 100.