A two-hole core drilling machine of the invention includes a body, a vertically reciprocating carriage vertically reciprocably mounted to the body, a fixing plate coupled to one side surface of the carriage, to rotatably support a drive shaft of a motor, a pivoting plate fastened to the fixing plate under a condition that a pivot angle of the pivoting plate is changed, a moving plate fastened to the pivoting plate under a condition that a length of the moving plate from the pivoting plate is varied, a belt or chain mounted between a drive pulley coupled to the drive shaft and a driven pulley coupled to a driven shaft rotatably mounted to the moving plate, a first core bit coupled to the drive shaft, and a second core bit coupled to the driven shaft.