To provide a brake operation device for a bicycle having an operation part of which the rotation can be detected by a detection means and which hardly obstructs brake operation, is non-breakable when the bicycle is fallen down, achieves operation feeling and operation efficiency almost unchangeable when an operation position or hand size varies and facilitates dust-proof and waterproof design.

In the brake operation device for the bicycle, an axial line 5 serving as the rotation center of the operation part 6 is arranged along a brake lever 4. The brake lever 4 is supported by a bracket 2 around an axial line 3 arranged in the bracket 2 so as to be swingable.