To provide a fan motor capable of controlling the air flow rate almost constant against a designated air flow rate even if it is a fan motor mounted with a DC motor switching current to armature windings based on a signal of a Hall IC, and a ventilator mounted with the same.

Since operation control is constantly performed at a stepwisely specified rotational frequency corresponding to a flow rate designated by an air flow rate specifying means 13 and an applied voltage range divided according to the designated flow rate. Thus, the fan motor and the ventilator can be obtained which are almost constantly controllable against a designated flow rate even if a conduction phase is changed by the influence such as the shifting of the mounting position to the substrate of the magnetic pole detection element of the Hall IC 5.