An automobile key operation mechanism comprising: a key cylinder; a locking lever that extends from a side surface of the key cylinder; an unlocking lever that extends from a side surface of the key cylinder in a direction that is different from the direction in which the locking lever extends; a locking pull line that is configured to lock a door of an automobile; and an unlocking pull line that is configured to unlock the door, wherein one end of the locking pull line is attached to the locking lever, wherein one end of the unlocking pull line is attached to the unlocking lever, and wherein, when the key cylinder rotates in a locking direction, the locking lever pulls the locking pull line, and, when the key cylinder rotates in an unlocking direction that is opposite the locking direction, the unlocking lever pulls the unlocking pull line, and wherein the key operation mechanism further comprises a support component that, when the key cylinder rotates in the locking direction, supports the locking pull line at a position at which the locking lever is at a greater distance away from the support component, and, when the key cylinder rotates in the unlocking direction, supports the unlocking pull line at a position at which the unlocking lever is at a greater distance away from the support component, characterized in that the support component is fixed to a housing and further includes a base plate screwed to an inner surface of the housing, an unlocking cable mounting wall and a locking cable mounting wall, the unlocking cable mounting wall and the locking cable mounting wall both projecting from the base plate toward the inside of the automobile. a key cylinder; a locking lever that extends from a side surface of the key cylinder; an unlocking lever that extends from a side surface of the key cylinder in a direction that is different from the direction in which the locking lever extends; a locking pull line that is configured to lock a door of an automobile; and an unlocking pull line that is configured to unlock the door, wherein one end of the locking pull line is attached to the locking lever, wherein one end of the unlocking pull line is attached to the unlocking lever, and wherein, when the key cylinder rotates in a locking direction, the locking lever pulls the locking pull line, and, when the key cylinder rotates in an unlocking direction that is opposite the locking direction, the unlocking lever pulls the unlocking pull line, and wherein the key operation mechanism further comprises a support component that, when the key cylinder rotates in the locking direction, supports the locking pull line at a position at which the locking lever is at a greater distance away from the support component, and, when the key cylinder rotates in the unlocking direction, supports the unlocking pull line at a position at which the unlocking lever is at a greater distance away from the support component, characterized in that the support component is fixed to a housing and further includes a base plate screwed to an inner surface of the housing, an unlocking cable mounting wall and a locking cable mounting wall, the unlocking cable mounting wall and the locking cable mounting wall both projecting from the base plate toward the inside of the automobile.