The invention relates to an angle adjuster. A diaphragm spring is arranged between the front end surface of a locking tooth plate and the inner end surface of a fixed seat, a rotation shaft extruding out of the fixed seat is provided with an unlocking handle, the inner bore of the unlocking handle is provided with a boss, the boss is stuck in the left rotation slot on the rotation shaft, and the locking tooth plate is engaged with inner teeth of an annular gear during locking; the locking tooth plate is in fit connection with the rotation shaft through the boss and grooves, the fixed seat is in fit connection with the rotation shaft through the boss and the grooves, the excircle of the rotation shaft is provided with the grooves, and inner pores of the locking tooth plate and the fixed seat are respectively provided with a boss; the rotation shaft is axially fixed on the locking tooth plate through sticking a clasp in the clasp slot of the rotation shaft; and the unlocking handle is axially positioned through sleeving the flange of the unlocking handle in the inner pore of an entity skeleton. The angle adjuster which allows all the teeth to be engaged with each other during locking is a stepless adjustable angle adjuster which can be locked at an arbitrary angle and has the advantages of large locking moment, simple structure and reliable working. The angle adjuster which can be applied to seat chairs and also can be used to adjust angles of other entities has a wide application range.