A synchronizing hinge includes a rotating module and a bracket plate unit. The rotating module includes two support units pivotably mounted to a base seat. Each support unit has a first support piece, a second support piece pivotably connected with the first support piece, and a moving axle extending through the first support piece and an arcuate slot of the second support piece and movably received in a moving slot of the base seat. The bracket plate unit includes two first bracket plates securely connected with the first support piece, and two second bracket plates securely connected with the second support piece. The support units and the bracket plate unit are rotatable between an initial position where the first bracket plates are flush with the second bracket plates, and a terminal position where the first bracket plates are inclined relative to the second bracket plates by an inclined angle.