Gear stage choosing apparatus, gear stage choosing method, and simulation apparatus

A gear stage choosing apparatus that chooses a gear stage of a stepped transmission included in a vehicle, the gear stage choosing apparatus comprising:

• one or more processors programmed to function as:
• a storage unit configured to store a shift map containing a relationship between vehicle speed and gear stage;
• and
• a determination unit configured to determine a gear stage associated with an estimated vehicle speed after a lapse of a first period of time from current time based on the shift map;
• an evaluation unit configured to evaluate fuel efficiency in each of some gear stages of multiple gear stages, the each of some gear stages including the determined gear stage and one or more gear stages higher or lower in less than or equal to a specific number of gear steps than the determined gear stage;
• and
• a choosing unit configured to choose a gear stage selected from among the each of some gear stages based on the fuel efficiency as a gear stage to which a current gear stage is changed.