© 2018 The Institute of Electrical Engineers of Japan. We investigated the shape of a well to trap single cells for the purpose of improving the cell trapping rate after cell seeding and liquid exchange in a cell microarray. The wells having vertical and inclined tapered side-wall were made using three-dimensional UV photolithography. Changes in cell trapping rate by the shape of the wells were evaluated by trapping tests with fluorescent microbeads and living cells. As a result of trapping test with living cells, bead residual rate of the microarray with inclined tapered wells is up to 2.9 times higher than that with vertical wells.