An optical information reading apparatus is provided which is made of an assembly of a barcode reader and a personal digital assistant (PDA). The barcode reader and the PDA are joined through an attachment. The barcode reader includes a joint detector working to detect the joint to the PDA and a communication system establishing communication with the PDA. The barcode reader works to transmit barcode data to the PDA through the communication system only when the joint detector has detected the joint to the PDA, thereby providing ease of operability, useability, etc.