To provide an attitude detecting mechanism for an IC of an automatic handler capable of detecting whether the IC is mounted normally on an IC socket in response to dispersion of IC package shapes or not, and capable of detecting thereby the attitude of the IC, by providing an area sensor of a wide detection range to detect a shading amount.

Sensor light sensitivity received by an area sensor lightreceiving side 1b in the case where an IC 4 is set normally onto an IC socket 2 is stored as 100% of reference value. When a detection determining reference value is, for example, 90% or less, it is determined that the IC 4 is not mounted normally on the IC socket 2 in the case where the sensor light sensitivity received by the area sensor receiving side 1b is changed from 100% at the time of a sensor light width C shown in (A) to 70% at the time of a sensor light width D shown in (B) to get lower than the detection determining reference value of 90%.