The utility model discloses an adjustable plug gauge. The plug gauge comprises a U-shaped handle and at least two bodies connected to the handle. The adjacent two bodies are parallel and overlapped. The handle comprises two parallel end portions, each end portion is provided with a through hole, and the two through holes are symmetrically arranged. Each body comprises a lengthening portion and a measuring portion measuring the electric clearance or the creep distance; one end of the lengthening portion is connected to the handle; the other end of the lengthening portion is connected to the measuring portion; and the end, not connected to the measuring portion, of the lengthening portion is provided with a penetrating hole; a first rotating shaft is arranged between the through holes and the penetrating hole of the body in a penetrating manner; and the lengthening portion and the measuring portion are in rotation connection through a second rotating shaft. During the measurement, by adjusting the angle between the handle and the bodies and the angle between each measuring portion and the corresponding lengthening portion, measuring parts can be directly measured without an electrical product being dismounted or the electrical product structure being destroyed, and therefore the measuring efficiency is improved and the loss rate of test samples is reduced.