The invention provides a bevel gear tooth thickness measurer, which comprises an operation table, a sine gauge, a mandrel, a right-angled curved ruler, a height gauge, a gauge block and a micrometer. The bevel gear tooth thickness measurer is characterized in that the sine gauge and the right-angled curved ruler are mounted at two ends of the operation table respectively, mounting angles of the sine gauge and the right-angled curved ruler are mutually parallel, the height gauge and an adjusting sleeve are arranged on the right-angled curved ruler and movably connected with the operation table, the micrometer with a holder, an anvil and a locking device removed is mounted on the adjusting sleeve, the micrometer is parallel to a basal plane of the operation table, an axillary steel ball is placed in the middle of a tooth space of the bevel gear to be measured and slightly close to a small end, and positioned in the middle of a contact area, and then relevant dimensional data are measured. The tooth thickness of a portion, where the steel is positioned, of the bevel gear is obtained by calculating, and the tooth thickness of a large end of the measured bevel gear is obtained. The bevel gear tooth thickness measurer can be used for measuring the thickness of optional-section teeth, especially in the middle of the contact area, and no back cone needs to be used as a measurement datum.