A ratchet opener comprises a rod body; a ratchet device having a seat; a top surface of the seat having two axial grooves; each groove being installed with a spring and a ratchet block; an adjusting sheet placed above the seat; and a ratchet sheet being installed above the adjusting sheet. Each ratchet block has a teethed inclined surface; the teeth surfaces of the two ratchet blocks are symmetrical to a center of the seal. A center of the adjusting sheet is installed with a second via hole; and the ratchet block is installed with a non-round buckling hole corresponding to the cylinder at the lower end of the rod body. In use, by controlling the adjusting sheet, the objects of unidirectional, bi-directional, and idle rotations are achieved. The operation is easy.