To provide a mechanical component mounting bracket having improved mounting accuracy.

In the state that the mounting face of an engine as a mechanical structure extends along an approximately vertical plane, the bracket 10 is fastened and fixed thereto via bolts inserted into a plurality of insertion holes 14A-20A. One insertion hole 14A is formed in a position eccentric downward from the center of the bolt by about 1/2 of a diameter difference between the insertion hole 14A and the bolt to be inserted therethrough. Another insertion hole 16A is formed in a position eccentric in the direction of rotating movement with gravity operating on the gravity center of the bracket 10 around the bolt inserted through the insertion hole 14A formed in the position eccentric downward, namely, in a horizontal direction of deviation from the gravity center of the bracket 10, by about 1/2 of a diameter difference between the insertion hole 16A and the bolt to be inserted therethrough.