The invention relates to a horizontal compressor which comprises a shell, a lower
flange, an air cylinder, an upper
flange and a motor. The lower
flange, the air cylinder, the upper flange and the motor are sequentially arranged in the shell. An
oil storage cavity is formed by the lower flange and the shell. A rotor is rotationally arranged in the air cylinder through a main shaft. The horizontal compressor further comprises a center oil hole penetrating the main shaft, a radial hole formed in the main shaft and communicating with the center oil hole, an oiling
pipe fixedly connected to the end, located in the
oil storage cavity, of the main shaft and communicating with the center oil hole, a lower flange
back pressure groove formed in the lower flange and communicating with a sliding piece installation groove of the rotor, a groove for communicating the lower flange
back pressure groove and the radial hole of the main shaft, an exhaust cavity communicating with an exhaust hole of the air cylinder and the center oil hole of the main shaft, and a fan installed at the other end of the fan, wherein the bottom end of the oiling
pipe is close to the bottom of the
oil storage cavity. According to the horizontal compressor, smooth stretching-out of a sliding piece during starting of the compressor and attachment between the sliding piece and the air cylinder during normal running of the compressor are effectively ensured. The invention further discloses a temperature adjusting device comprising the horizontal compressor.