The invention discloses a lever-type thickness measuring device. The lever-type thickness measuring device comprises a left support, a right support, measuring heads and sample rods, wherein the measuring heads are arranged at the two ends of the left support and the right support respectively, the middle parts of the left support and the right support are movably connected with each other through a pin shaft, the left support and the right support are divided into equal-length long ends and equal-length short ends which are symmetrically distributed to form the long-end measuring heads and the short-end measuring heads, the sample rods are arranged between the long-end measuring heads and the short-end measuring heads, the length of each sample rod is matched with the thickness of a workpiece to be measured, the length dimension tolerance of the sample rod is higher than the thickness dimension tolerance of the workpiece to be measured, and adjusting threads are arranged at the outer ends of the measuring heads and used for adjusting the distance between the two opposite measuring heads. The lever-type thickness measuring device disclosed by the invention utilizes two similar triangles formed by the left and right supports and the lever principle to measure the distances of two ends of the left and right supports so as to calculate the actual thickness of the workpiece to be measured, so that the purpose of measuring the thickness of a large-area plate is achieved.