Band saw

A band saw comprising a machine base, a conveyer mounted on said machine base for carrying the workpiece to be cut, a holder frame mounted on said machine base above said conveyer, a driving wheel and a driven wheel pivotally mounted on said holder frame, a saw blade mounted on said driving wheel and said driven wheel, a motor mounted on said holder frame and adapted to rotate said driving wheel and to further move said saw blade against the workpiece being carried on said conveyer, wherein a saw blade elevation adjustment structure is installed in said machine base for controlling the elevation of said holder frame above said machine base, said saw blade elevation adjustment structure comprising two vertical sleeves fixedly provided at said holder and arranged in parallel, a fixed nut fixedly provided at a top side of said holder frame on the middle between said two vertical sleeves, two vertical guide rods respectively inserted through said vertical sleeves and fixedly connected to said machine base, connecting frame affixed to said guide rods at a top side to support, a vertical motor mounted on said connecting frame, and a vertical screw rod threaded into said fixed nut and coupled to said vertical motor at said connecting frame for turning by said vertical motor at said connecting frame to move said holder frame along said guide rods.