We carried out line survey observations at the 26 - 30 GHz band toward the four high-mass star-forming regions containing hot cores , G10.30-0.15 , G12.89+0.49 , G16.86-2.16 , and G28.28-0.36 , with the Robert C. Byrd Green Bank Telescope . We have detected HC _ { 5 } N from all of the sources , and HC _ { 7 } N from the three sources , except for G10.30-0.15 . We further conducted observations of HC _ { 5 } N at the 42 - 46 GHz and 82 - 103 GHz bands toward the three sources , G12.89+0.49 , G16.86-2.16 , and G28.28-0.36 , with the Nobeyama 45 m radio telescope . The rotational lines of HC _ { 5 } N with the high excitation energies ( E _ { u } / k \sim 63 - 100 K ) , which are hardly excited in the cold dark clouds , have been detected from the three sources . The rotational temperatures of HC _ { 5 } N are found to be \sim 13 - 20 K in the three sources . The detection of the lines with the high excitation energies and the derived rotational temperatures indicate that HC _ { 5 } N exists in the warm gas within 0.07 - 0.1 pc radii around massive young stellar objects . The column densities of HC _ { 5 } N in the three sources are derived to be ( \sim 2.0 - 2.8 ) \times 10 ^ { 13 } cm ^ { -2 } . We compare the ratios between N ( HC _ { 5 } N ) the column density of HC _ { 5 } N and W ( CH _ { 3 } OH ) the integrated intensity of the thermal CH _ { 3 } OH emission line among the three high-mass star-forming regions . We found a possibility of the chemical differentiation in the three high-mass star-forming regions ; G28.28-0.36 shows the largest N ( HC _ { 5 } N ) / W ( CH _ { 3 } OH ) ratio of > 8.0 \times 10 ^ { 14 } in units of ( K km s ^ { -1 } ) ^ { -1 } cm ^ { -2 } , while G12.89+0.49 and G16.86-2.16 show the smaller values ( \sim 2 \times 10 ^ { 13 } ) .