Safety is a very important requirement in rehabilitation assist suits. We have proposed a velocity-based mechanical safety device (VBMSD) for an assist suit to aid flexion and extension of a patient’s knee joint. This VBMSD turns off the assist suit’s motor when an unintended high angular velocity of the knee joint occurs. Also, this VBMSD works even when the assist suit’s computer is out of order, because it consists of only passive mechanical components with no actuators, no controllers, or any batteries. In hospitals, however, not only knee joint assist suits, but also the other joint assist suits such as assist suits to aid flexion and extension of a patient’s elbow joint are needed. This VBMSD is too large to install to elbow joint assist suits. In this paper, we propose and develop a new compact VBMSD to be installed to an elbow joint assist suit. We call the new VBMSD the “miniVBMSD”. We present experimental results to check the effectiveness of the miniVBMSD.