An indexed gear-shift mechanism for a bicycle that has one lever for up-shifting and another lever for down-shifting. A ratchet wheel is fixed to the down-shifting lever and has two rows of teeth along an outer curvature thereof. A pair of pawls are placed on the up-shifting lever and works in conjunction with the two rows of teeth. A pair of springs respectively apply force on the levers in a counterclockwise direction. When a rider applies a force on the up-shifting lever in a clockwise direction, the pawls move to a next adjacent pair of teeth, one pawl preventing rotation of the lever and the other pawls preventing rotation of the ratchet wheel; the bicycle is in a higher gear. When a rider applies a force on the down-shifting lever in a clockwise direction, the pawls move to a previous adjacent pair of teeth, but the pawls do not prohibit movement of the down-shifting lever; therefore, the ratchet wheel may be down-shifted through as many gears as desired in one action.