The invention discloses a hole inner wall side chamfer punching device. The hole inner wall side chamfer punching device consists of a lower fixed plate (1), an insertion plate (2), a lower punch (3), a support column (4), a first pin (5), an upper fixed plate (6), an upper punch (7), a second pin (8), a bolt (9), a third pin (10) and a guide column (11), wherein the stand column (4) is a columnar structure with a section as an asymmetric ellipse; and R5 chamfer structures (43) are arranged at two semiarc contact ends of the asymmetric ellipse. The hole inner wall side chamfer punching device solves the problem of inner chamfer inclination caused by old locksmith drilling, guarantees the part inner chamfer machining quality, satisfies the clamping pin riveting force requirements, is particularly important in improvement of the product quality stability, and is important in application value in machining of other similar part structures.