A substrate transfer robot for transferring a substrate in a vacuum chamber, includes: a transfer arm platform having coupling holes, each compartmentalized into a lower and an upper space, wherein a link connecting member with blades is engaged at a front area of the transfer arm platform and a support shaft of a lower support is inserted into the lower space of one of the coupling holes; and a first and a second transfer arm part each including an end effector for supporting the substrate, multiple transfer link arms and subordinate link arms, and a common link arm that are connected to each other or to the transfer arm platform, wherein, for each transfer arm part, drive shafts, interlocked with transfer driving motors or speed reducers installed on one of the transfer link arms, and output shafts interlocked with the drive shafts are installed on the transfer link arms.