Abstract: A circular saw machine consists of a bed, a platform on top of the bed, a board secured in the bed, a swinging support, and a blade; the board has concentric curved slot and curved bar-shaped protrusion; the swinging support has a shaft portion, a curved groove, and a toothed bottom portion, and is joined to the board with the shaft portion being passed through the curved slot, and the curved bar-shaped protrusion fitted in the curved groove; a block with a groove is secured on the swinging support; a sliding block is fitted on the groove; a sleeve is secured on the sliding block, and a shaft is passed through the sleeve and joined to the blade; the blade sticks out through a slot of the platform; a hand-operated worm engages the toothed portion; the saw blade can be adjusted in angle leftwards and rightwards by turning the worm.