A recording/reproducing device includes a laser and a laser drive carried by a pickup having a drive for movement and an input for recording information. A control controls the drives to retrieve recording parameters from a predetermined portion of the recording medium, creates pulse sequences using the input recording information and retrieved recording parameters, and forms recording marks having recording mark lengths between a predetermined and maximum lengths, a top section, a last section including a cooling period, and an intermediate period. Heat of mark front edges is controlled by recording parameters for top sections that are classified according to recording mark lengths and recording parameters of the first through the maximum recording mark lengths are classified into a same group. Heat of mark rear edges is controlled by cooling start positions for cooling periods classified according to recording mark lengths.