The invention relates to the field of automation equipment, and in particular to a fool-proof detection device for a disconnecting switch. The device comprises a mechanical arm and a clamping assemblymounted on the mechanical arm, and also comprises a first sensor for detecting a cylindrical pin and a second sensor for detecting a fixed seat. The clamping assembly clamps the disconnecting switch,and the mechanical arm drives the clamping assembly to move to a set position. When the first sensor does not sense a sensing signal, the mechanical arm drives the clamping assembly to advance untilthe first sensor senses the sensing signal. If the second sensor does not sense the sensing signal at this time, the correct information is fed back. The two sensors are used for respectively detecting the cylindrical pin and the fixed seat of the disconnecting switch, thereby achieving the foo-proof detection of the disconnecting switch. The device can accurately take out a wrong disconnecting switch, so as to avoid the subsequent wrong marking.