The invention relates to a rock drilling device for a drill jambo. The rock drill device comprises a rock drilling arm component, a deflection hydraulic cylinder, a pitch hydraulic cylinder and a rock drilling mechanism. The deflection hydraulic cylinder is hinged to a deflection end of the rock drilling arm component to drive the rock drilling arm component to deflect; the pitch hydraulic cylinder is hinged to the deflection end of the rock drilling arm component to drive the rock drilling arm component to pitch; the rock drilling mechanism is connected with a telescoping end of the rock drilling arm component. The rock drilling device for the drill jambo has the advantages of wide working range, high movability, flexibility in operation, high stability and high quake resistance.