PURPOSE: To enable removal of a handrail stay from a clamp without cutting but as it is when a 'part of the clamp is buried in concrete as a result of concrete being placed in stairs after the handrail stay is mounted.

CONSTITUTION: In a mounting device for a temporary handrail 1 for stairs wherein a clamp 9 fitted in the upper end of a vertical plate P on the stair side is mounted on the lower end part of a stay 2 for the temporary handrail 1 for stairs, a body 7 of the clamp 6 comprises a base part 9 removably mounted on the lower end part of the stay 2, a sideways extension part 10 connected sideways from the base part 9, and a leg part 11 connected downward from the sideways extension part 10. A press bolt 8 to nip the vertical side plate P not between the base part 9 and the press bolt but between the lower end of the stay 2 and the press bolt is mounted in a sideways state on the body 7.