Abstract: The polysilicon thin film of the present invention is formed on a glass substrate or the like having a particulate product of SiO.sub.x (0<x.ltoreq.2) of size not more than 100 .ANG., for example, dispersed into not more than 100 pieces in an area of 0.1 .mu.m square. Furthermore, in the production method of a polysilicon thin film of the present invention, a particulate product of SiO.sub.x (0<x.ltoreq.2) of size not more than 100 .ANG., for example, dispersed into not more than 100 pieces in an area of 0.1 .mu.m square, is formed on a substrate, and thereafter a polysilicon thin film is grown using this particulate product as a nucleus.