A power generation equipment monitoring system includes a receiver and a determining processor. The receiver acquires, from a measuring device that measures output currents of power generation equipment that converts rotational energy of a rotor thereof into electric energy to output AC voltage with a reference frequency, waveform data representing waveform of the output currents. The determining processor determines presence and absence of a malfunction in a rotary block that applies motive power to the rotor of the power generation equipment, according to the waveform data acquired through the receiver. The determining processor determines the presence and absence of the malfunction based on a component of at least one specific frequency arranged at one or more intervals according to a rotational speed of the rotor from the reference frequency on a frequency axis in a frequency spectrum of the output currents.