The present invention relates to a front suction/discharge type outdoor unit for an air conditioner to provide an economical installation structure for efficiently installing a large capacity outdoor unit and provide services for easily transferring the outdoor unit, and examining, exchanging and repairing its components, by separating a suction casing and a discharge casing. The front suction/discharge type outdoor unit includes an outdoor unit suction casing having its one surface externally opened, and sucking external air for heat exchange, and an outdoor unit discharge casing being separated from or coupled to the outdoor unit suction casing, sucking external air through the outdoor unit suction casing, having its one surface externally opened, and discharging heat exchanged external air. Here, opened surfaces are respectively formed in the outdoor unit suction casing and the outdoor unit discharge casing to connect them to discharge the sucked external air.