A shift-drum apparatus for a gear-type transmission including a plurality of shift forks and a shift drum provided at its outer peripheral surface with a plurality of shift grooves, in which a state of the gear-type transmission is shifted between a neutral state and a plurality of transmission gear stages. The number of shift forks is the same as the number of the transmission gear stages, and each of the shift grooves includes one or more gear-shifting recesses that are depressed in an axial direction of the shift drum. The shift forks are biased in the axial direction respectively by springs toward the corresponding gear-shifting recesses. Two of the gear-shifting recesses are formed in at least one of the shift grooves, while two of the shift forks are engaged with the shift groove.