Abstract: A painting robot system includes a robot and a spray gun unit. The robot includes a plurality of robot arms and a drive shaft member disposed on a distal end robot arm of the multiple robot arms, the drive shaft member being rotatable about a distal end drive axis. The spray gun unit is mounted on the robot arm. The spray gun unit includes a support member fixed to the distal end robot arm, guide members disposed on the support member, a plurality of spray guns disposed on the support member, and a linkage mechanism connecting between the movable spray guns and the drive shaft member. A spacing between at least one pair of adjacent spray guns can be varied via the linkage mechanism by rotating the drive shaft member of the robot.