To propose technique for preventing the generation of the defect of oblique striking by detecting the "obliquely-gripping" of a workpiece conveyed in a transfer device for the workpiece which is provided on a multistage press device and a method of detecting the defective grip in the transfer device.

The transfer device for conveying the workpiece between forming stages which are provided on the multistage press device provided with a plurality of forming stages is provided with: a set of opening/closing type gripping pawls for gripping the workpiece; a displacement detecting means for detecting the amount of opening/closing stroke of the set of gripping pawls; a waveform calculating means for obtaining a waveform in which the amount of opening/closing stroke is arranged by a time series; a means for calculating the degree of similarity for calculating the degree of similarity between the above waveform and the waveform obtained from the amount of opening/closing stroke of the gripping pawls on normal operation which is preset and a determining means for determining whether the gripped state of the workpiece with the gripping pawls are good or not on the basis of the degree of similarity. A value on the basis of a Mahalanobis distance is calculated as the degree of similarity.