Instrument holding mechanical arm used for minimally-invasive robot

The invention provides an instrument holding mechanical arm used for a minimally-invasive robot, and relates to the instrument holding mechanical arm. The instrument holding mechanical arm solves the problems that the number of passive joints is large when an existing mechanical arm is arranged in a concentrated mode and the existing mechanical arm is large in overall size and low in rigidity when a passive arm is too long. The instrument holding mechanical arm comprises vertical horizontally-moving safety brake devices, passive joints, first joints, second joints and an integrated operative instrument drive device. One ends of the passive joints are arranged on the upper portions of the vertical horizontally-moving safety brake devices in a rotatable mode. One ends of the first joints are connected to the passive joints in a rotatable mode. One ends of the second joints are connected with the other ends of the first joints in a rotatable mode. The integrated operative instrument drive devices are arranged at the other ends of the second points. The instrument holding mechanical arm is used for operative instrument drive of the micro operative instruments of the robot.