The invention discloses a no-blind area welding device. The no-blind area welding device comprises a linear fit part. The invention further comprises a no-blind area welding method; and the no-blind area welding method is a method for welding by using a gun head of a welding gun to fit a straight line. A motor is adopted to driven the welding gun to swing; a guide base is used for fitting the gunhead of the welding gun as the straight line for welding; through a turning tendency of a magnetic base, workpiece welding lines can be copied without gaps; non-horizontal welding lines can be weldedthrough a magnetic force effect of the magnetic base; the welding is continued without needing manual subsequent repair welding; no welding defect occurs in joints to achieve high beauty; the controlis simple; and the function realization cost is low.