A mass flow sensor is provided with reduced zero point fluctuation, and a mass flow meter and a mass flow controller using the mass flow sensor, the mass flow sensor comprising a U-shaped flow path passage in which a fluid flows from first end to a second end, having a bottom portion and two straight portions connecting the bottom portion to the ends, a first thermal resistor wound around one of the straight portions, a second thermal resistor wound around the same straight portion as the first thermal resistor and provided away from the first thermal resistor toward the second end, and a heat dissipating portion provided so as to be in contact with the flow path passage on the side opposite to the second thermal resistor across the first thermal resistor.