A semiconductor integrated circuit device comprises: a circuit block formed on a semiconductor substrate; an electrically conductive pattern formed over a portion to be protected of the block; a resetting unit configured to reset a potential of a portion of the pattern to a reference potential; a connecting unit configured to connect the portion to a current supply line; and a detection circuit configured to determine whether a preset range includes a voltage of the portion when a predetermined time has elapsed since the portion is connected to the current supply line after the potential of the portion is reset to the reference potential is provided. A change in voltage of the portion depends on a circuit constant of the pattern.