The invention provides a transparent plastic container which is transparent, allows good design and enabls determination of authenticity by visual check with the use of light polarizing property. A transparent plastic sheet of a polystyrene-based resin having a total light transmission of 85% or higher and a haze of 7% or less is subjected to vacuum, pneumatic or vacuum/pneumatic forming at a sheet temperature ranging from a glass transition temperature plus 50 DEG C. to a glass transition temperature plus 130 DEG C., thereby obtaining a transparent plastic container having a planar portion with a strain amount of 150 nm or less.