In a frame structure configured so that front and rear frames 10, 30 are attached to an intermediate frame 20, the strength of each frame 10, 30 can be easily ensured, and the front frame 10 or the rear frame 30 can be prevented from being easily removed from the intermediate frame 20 when subjected to a large impact force.The front and rear frames 10, 30 are provided so that respective side face portions 12, 32 thereof overlap each other, and a plurality of protrusions 21 are provided on a side face of the intermediate frame 20. The frame 10 (30), whose side face portion 12 (32) is positioned on a laterally inner side, is attached to the intermediate frame 20 by latching engaging portions 13 (33), provided in the side face portion 12 (32), by the protrusions 21, respectively. On the other hand, the frame 30 (10), whose side face portion 32 (12) is positioned on a laterally outer side, is attached to the intermediate frame 20 by latching engaging portions 33 (13), provided in the side face portion 32 (12), by the protrusions 21, respectively.