A brake pedal apparatus includes: an operating pedal to be depressed so as
to be pivoted about a first axis; a pivot member pivotable about a second
axis parallel to the first axis, and connected to the operating pedal via
a connecting link so as to be pivoted about the second axis in response
to a depression of the operating pedal; and an output member to receive
an output generated upon pivot motion of the pivot member. The connecting
link is connected, at respective connected positions, to the operating
pedal and the pivot member. A relationship between a ratio of the output
to a depression force acting on the operating pedal, and an amount of the
depression of the operating pedal is changed depending upon the connected
positions of the connecting link. The brake pedal apparatus further
includes a ratio characteristic changing device operable, when the
depression force exceeds a predetermined value, to shift at least one of
the connected positions of the connecting link, for changing the
relationship between the ratio and the amount of the depression of the
operating pedal.