Crush box and vehicle bumper apparatus including the same

A crush box (20) arranged between a side member (10) of a vehicle body and a bumper reinforcement member (30), the crush box (20) including: a main body portion (21) arranged in a longitudinal direction of a vehicle and having a tubular shape and first and second portions (21 a, 21 b); a vehicle body attaching portion (22) arranged at a first end of the main body portion (21); and a bumper attaching portion (23) arranged at a second end of the main body portion (21), wherein a vertical cross-section of the first portion (21a) adjacent to the vehicle body attaching portion (22) is a polygonal shape and a vertical cross-section of the second portion (21 b) adjacent to the bumper attaching portion (23) is a circular or polygonal shape, and the number of vertices of the polygonal shape of the vertical cross-section of the second portion (21 b) is greater than the number of vertices of the polygonal shape of the vertical cross-section of the first portion (21 a).