Axicon produces a deep focused Bessel beam whose transverse focal spot is smaller than the size of an airy disk produced by conventional lens with the same numerical aperture. Rieko Arimoto et al. applied axicon to a beamscanning system and established the beam-scanning imaging system which is free from need of precise positioning. Meanwhile, the allowed amount of rotation is severely restricted due to the unwanted tilt in the focused ring. We analyze the tilt in the focused ring quantitatively and suggest an appropriate method of designing the aberration corrected lens. An exemplary lens design for 1° tilt in the scanning mirror is presented and it is shown that the amount of degradation is clearly suppressed in the optimized system.