A spot welding robot including a base and an arm assembly mounted on the base. The arm assembly includes a lower arm mounted at a lower end on the base for a swingable movement about a substantially horizontal first axis, a swingable member mounted on the lower arm at an upper end portion of the lower arm for a swingable movement about a second axis which is parallel with the first axis, and an upper arm mounted at one end portion on the swingable member for a swingable movement about a third axis which is perpendicular to the second axis. The swingable member has a portion extending in a direction opposite to the direction in which the upper arm extends. A driving motor is provided on the swingable member for driving the upper arm to produce the swingable movement of the upper arm about the third axis.
