The present invention is related to an apparatus and method for detecting a foreign object in a wireless power transmitting system. Specifically, a wireless power transmitting apparatus includes a primary core block which transmits wireless power to a wireless power receiving apparatus through magnetic induction or magnetic resonance; an electric driving unit applying an AC (Alternating Current) signal required for the primary core block to transmit the wireless power; a control unit being connected to the electric driving unit and generating a control signal for controlling the AC signal; and a current measurement unit measuring a current flowing into the primary core block and obtaining a current measurement value converted to a numeric value relevant for the control unit to analyze the current.