An ink supply device of a printing machine comprising an ink doctor chamber in which two doctor blades are attached detachably to an open edge of an ink groove of a housing, an anilox roll, and a position adjusting and fixing mechanism, wherein: the ink doctor chamber is supported to be movable by a frame between an attaching position close to the anilox roll where the doctor blades are abutted on the anilox roll and a maintenance work position away from the anilox roll where the doctor blades are separated from the anilox roll, the position adjusting and fixing mechanism has a first part for position adjusting and fixing (7a-1) and a second part for position adjusting and fixing (7a-2) which are attached to the frame, and parts to be position-adjusted and fixed (7b-1, 7b-2) provided on the housing, characterised in that: the first part for position adjusting and fixing (7a-1) and the second part for position adjusting and fixing (7a-2) are movable between fixing positions in abutment with the parts to be position-adjusted and fixed (7b-1, 7b-2) and releasing positions of fixation separated from the parts to be position-adjusted and fixed (7b-1, 7b-2), respectively, the first part for position adjusting and fixing (7a-1) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable away from the anilox roll but is fixed so as not to move toward the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing a moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll, and the second part for position adjusting and fixing (7a-2) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable toward the anilox roll, but is fixed so as not to move away from the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing the moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll. the ink doctor chamber is supported to be movable by a frame between an attaching position close to the anilox roll where the doctor blades are abutted on the anilox roll and a maintenance work position away from the anilox roll where the doctor blades are separated from the anilox roll, the position adjusting and fixing mechanism has a first part for position adjusting and fixing (7a-1) and a second part for position adjusting and fixing (7a-2) which are attached to the frame, and parts to be position-adjusted and fixed (7b-1, 7b-2) provided on the housing, characterised in that: the first part for position adjusting and fixing (7a-1) and the second part for position adjusting and fixing (7a-2) are movable between fixing positions in abutment with the parts to be position-adjusted and fixed (7b-1, 7b-2) and releasing positions of fixation separated from the parts to be position-adjusted and fixed (7b-1, 7b-2), respectively, the first part for position adjusting and fixing (7a-1) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable away from the anilox roll but is fixed so as not to move toward the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing a moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll, and the second part for position adjusting and fixing (7a-2) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable toward the anilox roll, but is fixed so as not to move away from the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing the moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll. the first part for position adjusting and fixing (7a-1) and the second part for position adjusting and fixing (7a-2) are movable between fixing positions in abutment with the parts to be position-adjusted and fixed (7b-1, 7b-2) and releasing positions of fixation separated from the parts to be position-adjusted and fixed (7b-1, 7b-2), respectively, the first part for position adjusting and fixing (7a-1) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable away from the anilox roll but is fixed so as not to move toward the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing a moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll, and the second part for position adjusting and fixing (7a-2) is constituted such that, as it is at the fixing position, the ink doctor chamber is movable toward the anilox roll, but is fixed so as not to move away from the anilox roll, together with this, the fixing position of the ink doctor chamber can be adjusted by changing the moving distance at the fixing position, and as it is at the releasing position of fixation, the ink doctor chamber is movable toward and away from the anilox roll.