To provide a curtain rail mounting bracket for securing a mounting height adjustment range, while preventing a bracket body from becoming larger and being deteriorated in outer appearance.

The bracket body 2 of the curtain rail mounting bracket is engaged with a base member 1 to be fixed onto a mounting surface 12 with the use of a mounting screw 8, so as to support the curtain rail R by the bracket body 2. The base member 1 includes holding means for attaining movability in a height direction with respect to the mounting surface 12 in a state where the mounting screw 8 is loosened, and performing stepwise holding.