In a band saw machine in which a pair of guide posts (7L, 7R) for guiding a saw blade housing that rotatably supports a driving wheel (17) and a driven wheel (21) and can vertically move in the vertical direction are provided between the driving wheel (17) and the driven wheel (21), an upper traveling part (23U) of a band saw blade (23) is disposed in the rear of the guide posts (7L, 7R) and a lower traveling part (23L) of a band saw blade (23U) is disposed in front of the guide posts (7L, 7R), when the band saw machine is viewed from the side, an intersection point between centers of the both wheels (17, 21) and the center line of the wheel width is almost equal to the width of the guide posts (7L, 7R).