Abstract: A foldable shoe sole (1) includes an upper sole (11) and a lower sole (12) fixed to an underside of the upper sole (11). The lower sole (12) includes first, second, and third sheets (121, 122, 123). The first sheet (121) is located between the second and third sheets (122, 123). The first sheet (121) includes triangular cross sections and has first, second, and third apexes. The first apex is located on an inner side of the foldable shoe sole (1). The second and third apexes are located on an outer side of the foldable shoe sole (1). A first groove (124) is formed between the second sheet (122) and a first side of the lower sole (12) extending between the first and second apexes. A second groove (125) is formed between the third sheet (123) and a second side of the lower sole (12) extending between the first and third apexes.