BUMPER JOINING STRUCTURE AND CRUSH BOX

Provided is a bumper joining structure, including: a bumper reinforcement having a front portion extending in a vehicle width direction, and a pair of flange portions extending from both edge portions of the front portion in a vehicle up-down direction, wherein the pair of flange portions include first joining portions; and a plurality of crush boxes arranged on the bumper reinforcement so as to be spaced apart from each other in the vehicle width direction, the plurality of crush boxes having a tubular shape which has a pair of end portions in a vehicle front-rear direction and side surfaces extending in the vehicle front-rear direction, wherein one of the pair of end portions is mounted to the front portion, and the side surfaces include second joining portions which join to the first joining portions.