Spark ignition type internal combustion engine

A spark ignition engine in which a thermal insulation layer is formed over a wall surface, facing an inside of a combustion chamber, of at least a part of base materials forming the combustion chamber, and mixture gas in the combustion chamber is ignited to burn the mixture gas, wherein:

• for a thermal conductivity λ [W/(m·K)], a thermal diffusivity κ [mm2/s], and a thickness L [μm] of the thermal insulation layer, relationships:
• (i) 16.7×λ≦L≦207.4×(κ)0.5,
• (ii) the thermal conductivity λ≦1.5 [W/(m·K)],
• (iii) the thermal diffusivity κ≦0.3 [mm2/s] are satisfied, and
• the thermal insulation layer comprises:
• a first part being a film layer formed of one or more of zirconia, silicon, titanium, and zirconium, organic silicon compounds carbon, oxygen, silicon, high-strength and high-heat endurance ceramic fibers, silica, alumina, silicon carbide, and silicon nitride,
• a second part being one or more of hollow ceramic beads, hollow glass beads, fine porous structure having an inorganic material, and silica aerogel,
• the second part of the thermal insulation layer is mixed into the first part such that the surfaces of the second part are entirely surrounded by the first part, and
• the first part is layered over the wall surface.