To provide an automatic sharpener that realizes continuous and automatic sharpening work of a curved saw.

A rotary table 2 with an inner circumference corresponding to a sawtooth edge of a curved saw to be formed includes saw plate holding mechanisms 23 corresponding to each process of prescribed sharpening work. Inside the rotary table, working mechanism parts 4 to 8 for respective successive processes of the prescribed sharpening work are arranged in the process order. An appropriate saw plate feeding and picking mechanism part 3 is disposed.