This is an easy one to identify because the hilt form is distinctive. The knife is Ilokano in manufacture, probably from Ilocos Sur. The hilt is called a sinan kapitan
or Antonio Luna
. The sheath is also typical Ilokano work. Your knife was probably made in the mid-20th C.
Antonio Luna was a Revolutionary War hero, and General of the Philippine Army in the Philippines-American War at the end of the 19th C. You can read more about Ilokano knives and their distinctive hilts in the excellent post by migueldiaz here