Provided is a temperature measuring device which includes: a flexible printed circuit board with wiring; a thermistor element; a heat collecting plate; and a pressing member. The flexible printed circuit board is configured to be attached to a case that is fixed to an object to be measured, the thermistor element is electrically connected to the wiring, the heat collecting plate is disposed on a side opposite to the thermistor element via the flexible printed circuit board so as to be pressed against a temperature measuring point in the object to be measured, and the pressing member is made of a foam material and is configured to be compressed when the case is fixed to the object to be measured and to press the heat collecting plate against the object to be measured.