FLAW DETECTION DEVICE

To detect a flaw in a steel plate deck from a pavement body side.SOLUTION: A flaw detection device comprises: an excitation coil 132; an excitation unit 210 that applies AC current to the excitation coil 132 to generate induction current in a steel plate deck through electromagnetic induction; a detection unit 230 that detects a detection signal based on the electromagnetic induction; an electromagnetic wave transmission and reception unit 250 that includes a transmission unit transmitting an electromagnetic wave and a reception unit receiving a reflected wave based on the transmitted electromagnetic wave; a distance calculation unit 262 that calculates the distance from the steel plate deck on the basis of the reflected wave; and a comparison unit 264 that compares the detection signal with a threshold based on the distance calculated by the distance calculation unit 262.SELECTED DRAWING: Figure 8 【課題】鋼床版のきずを舗装体側から検出する。【解決手段】探傷装置は、励磁コイル１３２と、励磁コイル１３２に交流電流を印加し、電磁誘導により鋼床版に誘導電流を発生させる励磁部２１０と、誘導電流に基づく検出信号を検出する検出部２３０と、電磁波を送信する送信部と、送信された電磁波に基づく反射波を受信する受信部とを備える電磁波送受信部２５０と、反射波に基づき、鋼床版との間の距離を算出する距離算出部２６２と、距離算出部２６２によって算出された距離に基づく閾値と、検出信号とを比較する比較部２６４と、を備える。【選択図】図８