A martensitic stainless steel product having a chromium content of 9 to 15%
by weight and a surface from which mill scales generated during production
are removed by a shot blasting. The surface satisfies that, when a color
image of the surface taken with 640.times.480 pixels is analyzed on blue
color and a histogram of the pixel numbers and the tones divided into 0 to
255 classes is obtained, a relationship between the maximum frequency Yp
and the tone value Xp at which Yp is counted satisfies an inequality,
800Xp-Yp-27000>0. This steel product is superior in weatherability
under atmospheric environments, and also superior in sulfide stress
cracking resistance under environments containing hydro-sulfide.