A steering device for a ratchet screwdriver includes a base. The base has a receiving hole defined therein. Two receiving grooves are defined in the base. A moving slot is comparted from receiving hole. A ratchet rod is partially received in the base. The ratchet rod includes a spindle and a ratchet wheel disposed on the spindle. Two blockers are respectively received in the two receiving grooves. Each blocker has unidirectional teeth formed on one end thereof for selectively engaging with the ratchet wheel. A housing is sleeved on the base. The housing has a protrusion disposed on an interior thereof for inserting into the moving slot.