We have succeeded in developing an ultrahigh-purity single-photon source at 1.5 m using a portable-type refrigeration system. Single-photons are emitted from a single InAs/InP quantum dot included in a quantum-dot chip. The quantum-dot chip and optical components are combined into a single body in order to reduce the effect of the vibration caused from the refrigerator. By using the refrigeration system and a well-controlled excitation pulse, we can obtain the lowest value of g(2)(0) = 4.2×10-4 at 8 K.