A brake-action synchronizing device for a two-wheeled vehicle includes a force imparting unit which is disposed in a housing and which includes a first block secured to and moved with a front brake cable, a stage extending transversely from the first block, and a second block which is disposed in the housing and which is secured to a rear brake cable. When the front brake cable is pulled by virtue of a front braking action, the first block is caused to move toward a ceiling wall of the housing and lift the second block so as to pull the rear brake cable, thereby delivering braking forces to both rear and front wheels of the vehicle.