A valve reference position-learning device for an internal combustion engine, which is capable of accurately learning the reference position of a valve both before and after the warm-up of the engine, while properly reflecting thereon a deviation of the reference position caused by the thermal elongation of the valve and drive system after the warm-up of the engine. The valve reference position-learning device calculates and updates a learned value of the reference position of the wastegate valve both at and after the start of the engine, by first and second learnings, respectively. The learned value calculated by the first learning is stored as an existing learned value. Further, at the start of the engine, if the calculation of the learned value is not completed, the learned value is set to the existing stored learned value.