A gear unit is basically provided with a gear and a unit case. The gear is arranged and configured to transfer rotation inputted from an external source to at least one driven member. The unit case defines an interior space for enclosing the gear and containing a lubricant to lubricate the gear. The unit case includes an output shaft opening and a lubricant passage. The output shaft opening is configured for connecting the driven member to the gear. The lubricant passage has an inlet provided adjacent the output shaft opening and a lubricant discharge outlet provided in a bottom portion of the unit case to convey lubricant between the output shaft opening and the lubricant discharge outlet.