There are provided a Ni-based thermal spraying alloy powder having excellent corrosion resistance and erosion-corrosion resistance even in an environment in which corrosion acts or corrosion and erosion act simultaneously, and a method for manufacturing an alloy coating. A Ni-based thermal spraying alloy powder comprising Cr: 15 wt % or more and 25 wt % or less, Mo: 0 wt % or more and 5 wt % or less, Si: 0.5 wt % or more and less than 2 wt %, Fe: 5 wt % or less, C: 0.3 wt % or more and 0.7 wt % or less, and B: 4 wt % or more and 7 wt % or less, with the balance being Ni and incidental impurities.
