The present invention provides a ratchet tool, wherein a circular tooth row is arranged into the round groove of the main body's actuating end. A tool driving seat is assembled rotatably onto the round groove of the main body. A first braking slot, a second braking slot and an arched control slot are triangularly configured onto the internal surface of the tool driving seat. The first and second braking slots are separately fitted with the first and second braking swing blocks. A moveable control gear is placed into the control slot and can shift to the through-hole at both ends of the control slot such that it is mated simultaneously with inner tip edges of the first and second braking swing blocks. An elastic resetter is additionally provided to make the first and second braking swing blocks with inner tip edge swing inwards in a normal state.