An intake temperature sensor capable of precisely detecting the temperature of intake at high speed even in a low air mass flow zone is provided. In an intake temperature sensor having a temperature detecting element 6 inserted in an opening provided in an intake pipe 3 to be disposed in the intake pipe, a temperature detecting element is mechanically joined with a heat sink 4 directly exposed to the flow of the intake flowing in the intake pipe, and the temperature of the intake is output based on an output obtained from the temperature detecting element. Thus, the thermal resistance of the temperature detecting element with respect to the intake flow can be reduced; therefore, the intake temperature sensor capable of precisely detecting the temperature of the intake at high speed even in the low air mass flow zone can be provided.