A pressure controller for an artificial respirator according to this invention includes a control valve facing a gas passage between an inspiratory gas inlet and an inspiratory gas outlet, and an elastic biasing means for elastically biasing the control valve against a valve seat. When an adjustment manipulating member moves backward, even the pivotal motion of the adjustment manipulating member does not operate an adjustment operating member. When the adjustment manipulating member is pulled out, the pivotal motion of the adjustment manipulating member operates the adjustment operating member, thereby adjusting the elastic biasing force of the elastic biasing means. This invention provides a pressure controller for an artificial respirator capable of reliably preventing unnecessary operating of the adjustment operating member although the pivoting operation of the adjustment manipulating member is simple as a whole, and there is no possibility that the adjustment manipulating member and the like are broken.