Provided are: an induction heating device allowing an efficient transfer of heat generated in a heating part to a heating medium flowing through a flow passage; and a power generation system equippedwith same. The induction heating device for heating a heating medium comprises: a rotating body having a rotating axis; a heating part disposed so as to face the rotating body with a gap therebetween;a magnetic flux generating part, provided on the rotating body, for generating magnetic flux toward the heating part; and a flow passage, provided along the heating part, wherethrough the heating medium flows. The flow passage has an inlet part for supplying the heating medium on one of the sides in the direction along the heating part, and an outlet part for discharging the heating medium on theother side. The gap between the magnetic flux generating part and the heating part is larger on the outlet part side of the flow passage than on the inlet part side.