A controlling device for synchronous folding pedals for bicycle includes bicycle pedal folding assembly. The assembly includes pedal base configured for pivotal connection with pedal cranks of the bicycle, braking ring and folding transmission subassembly. A foldable pedal is rotatably attached to the pedal base, and the pedal base has the first t axial line, the foldable pedal has the second axial line. The foldable pedal has a working position and a folded position along its rotating track. The braking ring is configured to reciprocate along the first axial line, and the braking ring drives the foldable pedal by the transmission subassembly shifting from the working position to the folded position. When folding pedals, only driving the braking ring can fulfill folding process of the foldable pedal, which operation is simplified and during the course of folding pedals, it is not necessary to touch the foldable pedals by hand.