A safety cap including a screw-type inner cap detachably mounted on a container mouth; and an outer cap that is combined with the inner cap so as to be rotatable relative to the inner cap. Each of the inner cap and the outer cap has a plurality of engaging protuberances. The engaging protuberances of the inner cap and the engaging protuberances of the outer cap are engaged with each other and rotate the inner cap when the outer cap is rotated while being pressed toward the inner cap. Each of the engaging protuberances has a vertical part that is engaged when the outer cap is rotated in a closing direction and an inclined part that is engaged when the outer cap is rotated in an opening direction. The inclined part has a steeply inclined part and a gently inclined part that is continuous with the steeply inclined part.