A brake temperature detection device: acquires a kinetic-energy based temperature rise, which is an increase in an amount of brake heat that occurs when kinetic energy generated in a running vehicle is converted into thermal energy by braking; acquires a braking-energy based temperature rise, which is an increase in an amount of brake heat that is calculated from an amount of work done when a brake's friction material is pressed against a friction target material; determines state of slope of a road surface on which the vehicle is running; and detects a brake temperature in accordance with an increase in an amount of brake heat generated in braking. The brake temperature detection device selects, based on the state of slope, either the kinetic-energy based temperature rise or the braking-energy based temperature rise as the increase in the amount of brake heat generated in braking and achieves brake temperature detection.