A power spring drive apparatus having a power spring on a power spring wind up shaft, an output shaft, and a gear train for winding the power spring and for transferring the rotational force of a wound power spring to the output shaft. The apparatus is in a housing case formed of first and second synthetic resin cases connected together by pins and receiving holes. The housing case has a power spring housing section with a window between the section and externally of the housing. One end of the power spring has a neck shape and extends through the window and is fastened to the housing.