Surroundings monitoring apparatus and program thereof

A surroundings monitoring apparatus (100) includes an obtaining portion (502) obtaining a first captured image data outputted by a first image capturing portion (16a, 16c) and a second captured image data outputted by a second image capturing portion (16b, 16d), and an output portion (512) superimposingly displaying an indicator (Pa, Qa) in at least one of a first display region (FV) and a second display region (SVL, SVR), in a case where the superimposed region of the indicator is included in the other of the first display region and the second display region, the output portion superimposingly displaying the indicator in the other of the first display region and the second display region in a display manner which corresponds to a display manner of the indicator displayed in the one of the first display region and the second display region.