1. A temperature estimating device which estimates temperatures of a target member of an apparatus constituent member constituting an electronic apparatus every period, wherein said electronic apparatus is configured to adjust braking force on a wheel mounted on a vehicle and is provided with a motor for braking, the device comprising: a heat generation amount calculating unit for calculating heat generation amount of the motor on the basis of a difference between an input energy corresponding value corresponding to input energy to the motor and an output energy corresponding value corresponding to output energy from the motor, wherein said input energy to the motor is calculated based on a current value flowing through the motor and a voltage value applied to the motor, and said output energy from the motor is calculated based on a number of rotations of an output shaft of the motor and driving torque of the motor; a heat radiation amount calculating unit for calculating heat radiation amounts from the target member on the basis of a difference between a previous temperature estimation value of the target member and an ambient temperature around the electronic apparatus, and thermal coefficient representing thermal characteristic of the target member; and an estimation value calculating unit for acquiring a temperature increase amount of the target member on the basis of a difference between the heat generation amount and the heat radiation amount calculated by the calculating unit, and calculating a current temperature estimation value of the target member on the basis of the temperature increase amount and the previous temperature estimation value of the target member.