A serial communication device includes: a data transfer unit configured to repeat storing a predetermined unit of data, received by a receiving unit, in a receiving buffer and transfer data to a storage unit when data of a predetermined size is accumulated in the receiving buffer; a counting unit configured to count one of the number of times the predetermined unit of data is stored and an amount of data accumulated; a monitoring unit configured to monitor a count value counted by the counting unit; and a data identifying unit configured to determine that a current interval is a non-communication interval during which a sending source does not send data if the count value remains unchanged for a predetermined time and identify first data, received after the determination of the non-communication interval, as beginning data of a sequence of data including a plurality of pieces of data.