NOVELTY - The battery (10) has a set of laminar sheets (16) including a negative electrode sheet (14) defining a negative electrode (30) in which a negative electrode active substance layer (28) in a form of a vapor-deposited polymer film (40) containing an active substance (38) is laminated integrally on surfaces of a negative electrode collector foil (26) in a form of a metallic foil. A solid electrolyte layer (32) in a form of a polymer film with lithium-ion conductivity is placed on sides of the negative electrode such that the electrolyte layer is laminated integrally on the substance layer.    USE - Small-sized solid type lithium-ion secondary battery for use as an electric power source used in a portable electronic device e.g. notebook personal computer and cellular or mobile phone.    ADVANTAGE - The battery permits effective reduction of size and sufficient improvement of performance owing to reduction of interface resistance between the solid electrolyte layer and positive and negative electrode active substance layers. The battery enables elimination of drying step and vapor-deposition polymerization process to permit a sufficiently high rate of film formation assure extremely effective reduction of required cycle time of production of the battery, so that the battery can be efficiently produced at sufficiently reduced cost. The battery allows positive and negative electrode active substance layers and solid electrolyte layers that do not have any distinct boundary interface, so that the battery having increased electron conductivity and ion conductivity and an improved output density can be stably and efficiently produced with a high degree of productivity, while effectively reducing required amount of the positive and negative collector foils and material cost of the battery.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for producing a lithium-ion secondary battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a lithium-ion secondary battery having a structure.    Small-sized solid type lithium-ion secondary battery (10)    Negative electrode sheet (14)    Laminar sheets (16)    Solid electrolyte layers (24, 32)    Negative electrode collector foil (26)    Negative electrode active substance layer (28)    Negative electrode (30)    Active substance (38)    Vapor-deposited polymer film (40)