In order to satisfy the potentially existing needs for steeper pool-type fishways, a preliminary experimental study on pool-type fishways with slope of 1 on 5 has been carried out using an 'endless' fishway model. This paper presents a theoretical approach to the steepest pool-type fishway and the results of the experimental approach focussing on baffle design and the rough evaluation using live fish. After some trials and errors in the baffle designing, an allowable flow on notches was obtained with a reasonably calm space in pools, in a baffle design where two slightly different baffles work in pairs. The fish release test showed that small fish can ascend the fishway with taking a rest at any pool of 25 cm length.