The second Akashiba power station is of a semi-underground type and located on a steep slope between the Arakawa River and a national road. Therefore, there were many such problems to be solved for its construction as safety precaution for steep slope ground including the closely located national road, underwater work for the intake and outlet works, construction of tunnel below the present water level of the river in which deluges can be expected. Very severe conditions were imposed for the plan of the retaining walls, which are required for the prevention of landslide on the national road side, because of the problems of boundaries of the site, proprietary right, etc. The plan and design were studied for 3 cases, i.e. during drilling, at regular time and at the time of earthquake occurrence. Outlines of the drilling of the power plant shaft, mucking, timbering, spraying and spring water treatment are given. In connection with the control of measurement, subjects for measurement and the result of measurement are reported. Although this construction work was carried out under very severe conditions, it was completed in August, 1990 with no serious disaster. 13 figs., 5 tabs.