Disclosed is a steel sheet including predetermined elements in each predetermined amount, with the balance consisting of iron and inevitable impurities, wherein a total area ratio of bainite, bainitic ferrite, martensite, residual austenite, and a martensite-austenite mixed structure is 95% or more and 100% or less, a total area ratio of ferrite and pearlite is less than 5%, an area ratio of the martensite-austenite mixed structure is 5% or more and 30% or less, an average section length of the martensite-austenite mixed structure is 0.32 μm or less, and a proportion of an area of a region in ferrite, bainitic ferrite, and martensite where no cementite is present to the total area of ferrite, bainitic ferrite, and martensite is 3.0% or more and 5.0% or less.