A periphery monitoring apparatus includes: an acquisition unit (512) configured to acquire first image data that is captured by a first imaging unit (16b) provided on a left side of a vehicle body (2), and second image data that is captured by a second imaging unit (16d) provided on a right side of the vehicle body; and an output unit (514) configured to combine third image data which is generated by rotating, and magnifying or minifying the first image data in such a way that a plurality of left reference points included in the first image data are respectively displayed at preset positions, and fourth image data which is generated by rotating, and magnifying or minifying the second image data in such a way that a plurality of right reference points included in the second image data are respectively displayed at pre-set positions, and to output the combined image data.