To provide a device for measuring the minute torque and torque ripple of a micro motor in which the speed depending property of load torque is reduced, and the torque ripple of the micro motor has no influence on the fluctuation of load torque.

This device is provided with a measuring shaft 4 having a motor mounting part for fixing a motor to be measured on one end and an extension shaft 42 on the other end, an air bearing 3 for supporting the measuring shaft 4 in no contact, a viscous fluid brake 1 making fluid contact with one end of the movable shaft of the motor to be measured, a sensor 7 for measuring the rotation of the movable shaft of the motor to be measured in no contact, a joint 5 fixed to the end part of the extension shaft 42, extended radially and connected to an electronic force balance, and an electronic force balance 6 for measuring the displacement of the joint 5 by converting it into load, and as the member making fluid contact in the viscous fluid brake 1, a colloid solution type electroviscous fluid or liquid crystal type electroviscous fluid is used.