An apparatus for controlling a driving mode of a vehicle, comprising: a) a driving information detector configured to detect driving information to determine driving tendency; and b1) a controller configured to calculate a short term driving tendency index (210; SI_short(%)) based on the driving information and operate at least one of an engine and a transmission into a sport mode or a normal mode based on the short term driving tendency index satisfying a predetermined entrance and release condition, b2) the short term driving tendency index being calculated over a short term predetermined time and indicating with a low value a mild driving tendency of the driver with a gentle acceleration habit and a defensive driving pattern and indicating with a high value a sport driving tendency of the driver with a rapid acceleration habit and an aggressive driving pattern; c) wherein the controller is configured to calculate a middle term driving tendency index (220; SI_med(%)) using the short term driving tendency index, the middle term driving tendency index being calculated over a middle term predetermined time greater than the short term predetermined time by calculating a cumulative distributing or cumulative averaging of the short term driving tendency index, determine a delay time (T_med_OFF) for maintaining the sport mode using the middle term driving tendency index (SI_med(%)), enter (S335, S345) a sport mode from a normal mode based on the short term driving tendency index (SI_short(%)) when the short term driving tendency index (SI_short(%)) becomes greater or equal to an entrance condition value (SI_SPO_ON), and release the sport mode to the normal mode after the delay time (T_med_OFF) from a condition satisfaction time at which the short term driving tendency index (SI_short(%)) becomes equal or less than a releasing condition value (SI_SPO_OFF) of the sport mode. a) a driving information detector configured to detect driving information to determine driving tendency; and b1) a controller configured to calculate a short term driving tendency index (210; SI_short(%)) based on the driving information and operate at least one of an engine and a transmission into a sport mode or a normal mode based on the short term driving tendency index satisfying a predetermined entrance and release condition, b2) the short term driving tendency index being calculated over a short term predetermined time and indicating with a low value a mild driving tendency of the driver with a gentle acceleration habit and a defensive driving pattern and indicating with a high value a sport driving tendency of the driver with a rapid acceleration habit and an aggressive driving pattern; c) wherein the controller is configured to calculate a middle term driving tendency index (220; SI_med(%)) using the short term driving tendency index, the middle term driving tendency index being calculated over a middle term predetermined time greater than the short term predetermined time by calculating a cumulative distributing or cumulative averaging of the short term driving tendency index, determine a delay time (T_med_OFF) for maintaining the sport mode using the middle term driving tendency index (SI_med(%)), enter (S335, S345) a sport mode from a normal mode based on the short term driving tendency index (SI_short(%)) when the short term driving tendency index (SI_short(%)) becomes greater or equal to an entrance condition value (SI_SPO_ON), and release the sport mode to the normal mode after the delay time (T_med_OFF) from a condition satisfaction time at which the short term driving tendency index (SI_short(%)) becomes equal or less than a releasing condition value (SI_SPO_OFF) of the sport mode.