An obstacle detection stopping device of a solar radiation shielding apparatus capable of suppressing the wear of a lifting cord due to the contact of a slat with the lifting cord. The obstacle detection stopping device (10) comprises a support member (11), a rotary drum (13), a cam clutch (12), and a winding pulley (9). A drive shaft (8) is passed through the inside of the device. A rotating force in the unwinding direction is transmitted to the drive shaft (8) by a tension applied to the winding pulley (9). The rotary drum (13) is integrally fitted to the drive shaft (8), and the cam clutch (12) is fitted to the outer edge thereof so as to be rotated relative to each other. Based on the relative rotation of the cam clutch (12) to the rotary drum (13), the cam clutch (12) is moved along its axial direction to change the state of its engagement with a braking projected part (11g). The cam clutch (12) is installed so as to be non-rotated relative to the winding pulley (9). When the tension applied to the winding pulley (9) is eliminated, the cam clutch stops its rotating motion together with the winding pulley (9), and based on the relative rotation thereof to the rotary drum (13), the cam clutch is engaged with the braking projected part (11g).