An imperfect combustion detecting device includes a destructive current supplying means which supplies, under a condition that it is determined by a useful life determining means that a deterioration status corresponding value matches a use limit value, destructive current to a sensor in order to melt down a part of a circuit that configures the sensor. The knee joint prosthesis includes a tibial tray and a bearing member that engages the tibial tray. The flow turning device forms an air flow pathway having a substantially 180\xb0 turn. The leads are connected to internal gate terminals. The location of the cursor relative to the enlarged region is co-located with the location of the cursor relative to the selected region such that the locations are identical.