A foamed sheet according to the present invention has a thickness of 30 to 500 μm and includes a foam. The foam has a density of 0.2 to 0.7 g/cm3, an average cell diameter of 10 to 150 μm, and a peak top of loss tangent (tan δ) occurring in a temperature range of from −30° C. to 30° C., where the loss tangent is defined as the ratio of a loss modulus to a storage modulus determined at an angular frequency of 1 rad/s in dynamic viscoelastic measurement of the foam. The foam preferably has a maximum of the loss tangent (tan δ) in the temperature range of from −30° C. to 30° C. of 0.2 or more.