Method and apparatus for measuring metal exposure in resin covering portion in metal container and constituent member thereof

Disclosed is a method for measuring the metal exposure in a resin covering area of a metal container or a constituent member thereof, which comprises contacting the resin covering area of the metal container or the constituent member thereof with a measuring electrode through an electrolytic solution, relatively moving the resin covering area and the measuring electrode in a certain direction while always holding the electrolytic solution between the measuring electrode and the resin covering area, measuring a leak current between the metal substrate of the metal container or constituent member at predetermined pitches and detecting the metal exposure of the resin covering area as leak currents at respective parts discriminately. According to this measuring method, the degree of the metal exposure can be easily measured as the leak current at respective parts discriminately, and statistical processing of the measured leak current values can be easily performed.