A marine reduction and reverse gear unit having an output shaft disposed at an acute (or obtuse) angle with respect to an input shaft 7 comprises: a drive gear 15 for transmitting torque from the input shaft 7; first and second driven gears 30, 31 engaged with the drive gear and disposed on the right and left sides thereof to sandwich the drive gear between the first and second driven gears; a reverse gear 16 connected to the drive gear 15 via a reverse hydraulic clutch 16; a first forward speed gear 33 connected to the first driven gear 30 via a hydraulic clutch; a second forward speed gear connected to the second driven gear 31 via a hydraulic clutch; and an output gear 26 fixed on the output shaft and engaged directly with one of the reverse gear 16, first forward speed gear 33 and second forward speed gear 36, or engaged therewith via idle gears to thereby receive the transmitted torque. This marine reduction and reverse gear unit provides a stable boat speed and enhanced acceleration performance by increasing the number of engine revolutions when wakeboarding.