Optical information reading device and optical information reading method

An optical information reading device 100 includes an aiming module 60 configured to irradiate aiming light for instructing an imaging area of image data generated by an imaging module, a trigger switch 30 for starting imaging processing by the imaging module, an aiming switch 43B for causing the aiming module 60 to irradiate the aiming light, and a reading unit 81 configured to read information of the symbol. The reading unit 81 is configured to, in an aiming state in which irradiation processing for the aiming light by the aiming module 60 is executed by operation of the aiming switch 43B, detect that the trigger switch 30 is operated and read, based on the image data generated by the imaging processing of the imaging module, information of the symbol included in a predetermined partial area PA corresponding to an irradiation position of the aiming light.