Stainless steel material for diffusion bonding jig

Provided is a stainless steel material for a diffusion bonding jig in which deformation of bonding members is suppressed while maintaining diffusion bonding properties of the bonding members, and in which releasability (detachability of a bonding member from a release member) after diffusion bonding treatment is excellent. An embodiment of the present invention provides a stainless steel material for a diffusion bonding jig having excellent deformation suppressibility and releasability, the material being a stainless steel material including 1.5 mass % or more of Si, and a ratio (Fr/Fp) of the high-temperature strength (Fr) of the stainless steel material at 1000° C. to the high-temperature strength (Fp) of a bonding member at 1000° C. being 0.9 or more, the bonding member to be bonded by diffusion bonding. The stainless steel material preferably includes C: 0.1 mass % or less, Si: 1.5 to 5.0 mass %, Mn: 2.5 mass % or less, P: 0.06 mass % or less, S: 0.02 mass % or less, Ni: 8.0 to 15.0 mass %, Cr: 13.0 to 23.0 mass %, and N: 0.2 mass % or less.