A thermal spray powder is provided that contains, as constituent elements, a first element selected from W and Mo; a second element selected from Co, Ni, and Fe; a third element selected from C and B; and a fourth element formed of Si. The amount of the second element in the thermal spray powder is 40% by mole or less. The mole ratio of the fourth element to the second element in the thermal spray powder is 0.002 or greater and 0.03 or less. The thermal spray powder has a crystal phase containing Co, Ni, or Fe; W; and C or a crystal phase containing Co, Ni, or Fe; W or Mo; and B. In an X-ray diffraction spectrum of the thermal spray powder, the peak intensity attributed to Co, Ni, or Fe is at most 0.1 times the largest peak intensity in the same X-ray diffraction spectrum.