To make a small-sized optical system for irradiation which linearly irradiates an image information recording medium with irradiation light and an optical system for convergence which converges emitted or reflected light from the image information recording medium.

A sheet 50 is linearly irradiated with the light L from an exciting light source by using fibers Fa for irradiation which is arrayed as shown by an arrow X and the stimulated phosphorescent light M emitted by the sheet 50 by the irradiation with the exciting light L is converged on respective photoelectric conversion elements 21 of a line sensor 20 by using fibers Fb for convergence which are arrayed as shown by the arrow X; and the fibers Fa for irradiation and fibers Fb for convergence area united.