To provide a vehicle body front part structure capable of securing expected collision energy absorption due to crushing deformation of a front main frame at a collision time with a simple constitution.

This vehicle body front part structure 1 includes the front main frame 10 provided with a front part 11, a kickup part 12 and an extension part 13, and a sub frame 20 in which a front end part 21a and a rear end part 22 are fastened and fixed to the front part 11 and the kickup part 12. The sub frame 20 is bent and deformed downward according to the crushing deformation of the front main frame 10 in the head-on collision. In the structure 1, a fastening bolt 40 having a distal end part 41 projecting into the kickup part 12 is fixed to the rear end part 22, and the kickup part 12 includes an interference member 37 opposed to the distal end part 41 of the fastening bolt 40. The distal end part 41 of the fastening bolt 40 abuts on the interference member 37 according to bending deformation of the sub frame 20 to prevent rising deformation of the kickup part 12 and to stably absorb collision energy of the front main frame 10.