A spark ignition type internal combustion engine comprising: a variable compression ratio mechanism that changes a mechanical compression ratio; and a variable valve mechanism (B, C) that changes a first valve characteristic of an intake valve or an exhaust valve, wherein the variable valve mechanism (B, C) is mechanically coupled to the variable compression ratio mechanism, and the variable valve mechanism (B, C) is controlled in accordance with a compression ratio-changing operation amount of the variable compression ratio mechanism, and the first valve characteristic of the intake valve or the exhaust valve in the variable valve mechanism (B, C) is controlled in accordance with the compression ratio-changing operation amount of the variable compression ratio mechanism, wherein the variable compression ratio mechanism changes the mechanical compression ratio by relatively moving a crankcase and a cylinder head with respect to each other, and the variable valve mechanism (B, C) is controlled in accordance with a relative positional relationship between the crankcase and the cylinder head, characterised in the spark ignition type internal combustion engine further comprising a phase angle-changing mechanism that changes a second valve characteristic of the intake valve or the exhaust valve, which is different from the first valve characteristic that is changed by the variable valve mechanism (B, C), the phase angle being a crank angle that occurs when the lift of the intake valve or the exhaust valve peaks, wherein the phase angle-changing mechanism is a timing-related mechanism that is mechanically coupled to the variable compression ratio mechanism and to the variable valve mechanism (B, C). a variable compression ratio mechanism that changes a mechanical compression ratio; and a variable valve mechanism (B, C) that changes a first valve characteristic of an intake valve or an exhaust valve, wherein the variable valve mechanism (B, C) is mechanically coupled to the variable compression ratio mechanism, and the variable valve mechanism (B, C) is controlled in accordance with a compression ratio-changing operation amount of the variable compression ratio mechanism, and the first valve characteristic of the intake valve or the exhaust valve in the variable valve mechanism (B, C) is controlled in accordance with the compression ratio-changing operation amount of the variable compression ratio mechanism, wherein the variable compression ratio mechanism changes the mechanical compression ratio by relatively moving a crankcase and a cylinder head with respect to each other, and the variable valve mechanism (B, C) is controlled in accordance with a relative positional relationship between the crankcase and the cylinder head, characterised in the spark ignition type internal combustion engine further comprising a phase angle-changing mechanism that changes a second valve characteristic of the intake valve or the exhaust valve, which is different from the first valve characteristic that is changed by the variable valve mechanism (B, C), the phase angle being a crank angle that occurs when the lift of the intake valve or the exhaust valve peaks, wherein the phase angle-changing mechanism is a timing-related mechanism that is mechanically coupled to the variable compression ratio mechanism and to the variable valve mechanism (B, C).