A communication device (10) communicates with a communication device (20) in each of time divisions defined by shared time that is shared with the communication device (20). The communication device (10) includes a clocking unit (11) that measures the shared time, an acquirer (13) that acquires, from the communication device (20), error information about a first error of the communication device (20) in measuring the shared time, and a specifier (14) that specifies, to the communication device (20), a suspension duration at least at a start or at an end of each of the time divisions. The suspension duration is a duration for which the communication device (20) suspends data transmission. The suspension duration specified by the specifier (14) is greater than or equal to a greater error of the first error and a second error that is an error of the clocking unit (11) in time measurement.