A high-performance semiconductor device using an SOI substrate in which a low-heat-resistance substrate is used as a base substrate. Further, a high-performance semiconductor device formed without using chemical polishing. Further, an electronic device using the semiconductor device. An insulating layer over an insulating substrate, a bonding layer over the insulating layer, and a single-crystal semiconductor layer over the bonding layer are included, and the arithmetic-mean roughness of roughness in an upper surface of the single-crystal semiconductor layer is greater than or equal to 1 nm and less than or equal to 7 nm. Alternatively, the root-mean-square roughness of the roughness may be greater than or equal to 1 nm and less than or equal to 10 nm. Alternatively, a maximum difference in height of the roughness may be greater than or equal to 5 nm and less than or equal to 250 nm.