An electric arc detection apparatus comprising: a current sensor configured to detect an electric current flowing through a power line (22a, 22b) that connects a direct current power supply and a power conversion circuit; a power spectrum conversion portion configured to generate a power spectrum from an output signal of the current sensor; an electric arc detection portion configured to detect a suspected electric arc based on a high-frequency component of the power spectrum; a pseudo electric arc determining portion configured to determine whether a pseudo electric arc has been generated based on a low-frequency component of the power spectrum; and an electric arc presence/absence determining portion configured to determine that there is an electric arc if the electric arc detection portion detects a suspected electric arc and the pseudo electric arc determining portion determines that a pseudo electric arc has not been generated, and to determine that there is no electric arc if the electric arc detection portion detects a suspected electric arc and the pseudo electric arc determining portion determines that a pseudo electric arc has been generated, characterized in that the pseudo electric arc determining portion is configured to determine that the electric arc is a pseudo electric arc if a first activation condition is satisfied a predetermined number of times or more, and the first activation condition includes a condition that power of a first period having highest power in the low-frequency component of the power spectrum is greater than a first threshold and a condition that power of a harmonic or fractional frequency of the first period is greater than a second threshold. a current sensor configured to detect an electric current flowing through a power line (22a, 22b) that connects a direct current power supply and a power conversion circuit; a power spectrum conversion portion configured to generate a power spectrum from an output signal of the current sensor; an electric arc detection portion configured to detect a suspected electric arc based on a high-frequency component of the power spectrum; a pseudo electric arc determining portion configured to determine whether a pseudo electric arc has been generated based on a low-frequency component of the power spectrum; and an electric arc presence/absence determining portion configured to determine that there is an electric arc if the electric arc detection portion detects a suspected electric arc and the pseudo electric arc determining portion determines that a pseudo electric arc has not been generated, and to determine that there is no electric arc if the electric arc detection portion detects a suspected electric arc and the pseudo electric arc determining portion determines that a pseudo electric arc has been generated, characterized in that the pseudo electric arc determining portion is configured to determine that the electric arc is a pseudo electric arc if a first activation condition is satisfied a predetermined number of times or more, and the first activation condition includes a condition that power of a first period having highest power in the low-frequency component of the power spectrum is greater than a first threshold and a condition that power of a harmonic or fractional frequency of the first period is greater than a second threshold.