An ignition timing control device for an internal combustion engine, comprising: knock control means for performing ignition timing control such that knocking of the internal combustion engine is at or below a predetermined level; the ignition timing control device being characterized in that it further comprises: first cylinder volume calculation means for calculating a cylinder volume (V base1) at a predetermined fraction burned crank angle where a predetermined fraction burned is greater than 0% (e.g. 50%) during a combustion stroke made with first base ignition timing (SA base1) when an engine operational status is in a first operating state (NE 1, KL 1); second cylinder volume calculation means for calculating a cylinder volume (V KC1) at the predetermined fraction burned crank angle during a combustion stroke made with ignition timing obtained through the ignition timing control by the knock control means when the engine operational status is in the first operating state (NE 1, KL 1); cylinder volume rate learning means for calculating a cylinder volume rate ((V KC1 -V base1)/V base1) which is a value obtained by dividing, by the cylinder volume (V base1) calculated by the first cylinder volume calculation means, a difference as a remainder after the cylinder volume (V base1) calculated by the first cylinder volume calculation means is subtracted from the cylinder volume (V KC1) calculated by the second cylinder volume calculation means and storing the calculated cylinder volume rate as a learning value; third cylinder volume calculation means for calculating a cylinder volume (V base2) at the predetermined fraction burned crank angle during a combustion stroke made with second base ignition timing (SA base2) when the engine operational status is in a second operating state (NE 2, KL 2) different from the first operating state (NE 1, KL 1); and setting means for setting learned ignition timing which is ignition timing as an initial value at the time of ignition timing control by the knock control means when the engine operational status is in the second operating state (NE 2, KL 2), the setting means setting the learned ignition timing such that the learned ignition timing is retarded and a cylinder volume at the predetermined fraction burned crank angle during a combustion stroke made with the learned ignition timing increases with increase in the learning value. knock control means for performing ignition timing control such that knocking of the internal combustion engine is at or below a predetermined level; the ignition timing control device being characterized in that it further comprises: first cylinder volume calculation means for calculating a cylinder volume (V base1) at a predetermined fraction burned crank angle where a predetermined fraction burned is greater than 0% (e.g. 50%) during a combustion stroke made with first base ignition timing (SA base1) when an engine operational status is in a first operating state (NE 1, KL 1); second cylinder volume calculation means for calculating a cylinder volume (V KC1) at the predetermined fraction burned crank angle during a combustion stroke made with ignition timing obtained through the ignition timing control by the knock control means when the engine operational status is in the first operating state (NE 1, KL 1); cylinder volume rate learning means for calculating a cylinder volume rate ((V KC1 -V base1)/V base1) which is a value obtained by dividing, by the cylinder volume (V base1) calculated by the first cylinder volume calculation means, a difference as a remainder after the cylinder volume (V base1) calculated by the first cylinder volume calculation means is subtracted from the cylinder volume (V KC1) calculated by the second cylinder volume calculation means and storing the calculated cylinder volume rate as a learning value; third cylinder volume calculation means for calculating a cylinder volume (V base2) at the predetermined fraction burned crank angle during a combustion stroke made with second base ignition timing (SA base2) when the engine operational status is in a second operating state (NE 2, KL 2) different from the first operating state (NE 1, KL 1); and setting means for setting learned ignition timing which is ignition timing as an initial value at the time of ignition timing control by the knock control means when the engine operational status is in the second operating state (NE 2, KL 2), the setting means setting the learned ignition timing such that the learned ignition timing is retarded and a cylinder volume at the predetermined fraction burned crank angle during a combustion stroke made with the learned ignition timing increases with increase in the learning value.