PURPOSE: To evaluate the performance of a printing magnetic hammer group, by a method wherein an impact sensor is moved along a printing magnetic hammer group to a position corresponding individually to a printing hammer, and an output from the sensor is compared with a plurality of threshold values, and is sorted.

CONSTITUTION: By driving a motor 5, the impact sensor 3 is moved along the printing magnetic hammer group 1 while being guided by a guide shaft mechanism 4, and receives an impact individually from each of the printing hammers 1a. Threshold value generating circuit 12, 13 generate threshold values VH, VL, which are compared with the output VO of the sensor 3. When VH>VO>VL, a signal is simply outputted from a comparing circuit 10 to an AND circuit 10. Then, an indication output is marked in a column of G (Acceptable) as indicated for No.3 in an indication format.