A waterproof pressure sensor includes a pressure detection element, a cavity package configured to be provided with a recess in which the pressure detection element is mounted and an edge provided around the recess, a frame configured to be attached to the edge of the cavity package and has a surface more smoothed than the edge and an opening, a contact prevention member configured to be attached to the frame, and a pressure introducing hole having a diameter smaller than a diameter of the opening at a position overlapping the opening, and a gel agent configured to be provided in the recess and the opening, in which the gel agent is provided to be separated from an edge of the pressure introducing hole on the frame side.