PURPOSE: To attain to enhance the reliability of a test, by keeping the contact of a friction piece and the rotary surface of a rotor when no pressing force is acted thereupon.

CONSTITUTION: The holder 4 supported by a stand 5 through a linear bearing 6 is constituted so as to hold a friction piece 3 and to enable the same to be pressed to the rotary surface 2 of a rotor 1. The load of a wt. 10 is imparted to the holder 4 as moving force through a pulley 8 and a wire 9, and said moving force is set to the direction for pressing the friction piece 3 to the rotor 1. By this method, the friction piece 3 is always contacted with the rotary surface 2 of the rotor 1 and, further, predetermined pressing force is imparted to said friction piece 3 from a pressing arm 7 at the time of necessity and the friction state thereof is made approximate to an actual friction material use state. Therefore the enhancement in the testing reliability of the friction material can be achieved.