PURPOSE: To effectively prevent oil leakage from a welded part between a main shaft and a crank by eccentrically connecting the main shaft to the crank through welding dots.

CONSTITUTION: A crankshaft 14 of a compressor 10 is constituted by integrally connecting two parts of a hollow pipe-shaped main shaft 17 and a crank 18 by welding. Disk parts 20, 21 are formed in a flange shape in a welding part of the main shaft 17 to the crank 18. The main shaft 17 forms in its disk part 20 a supply oil hole 22 in an eccentric position, while drilling an oil hole 23 communicating with a lubricating part of the main shaft 17. While the crank 18 forms in the end face of its disk part 21 two or more welding dots 25 protruding to the bottom, and each welding dot 25 is arranged, for instance, on the same circumference.