The Equator is the line that divides the Earth into two equal halves. It is equidistant from both the North and the South Poles and lies at 0° latitude. The half of Earth that lies north of Equator is Known as Northern Hemisphere and other half which lies south of Equator is known as Southern Hemisphere.

The Equator moves through four continents namely South America, Africa, Asia, and Oceania.

The Equator passes through the land of 11 countries namely - Ecuador, Columbia, Brazil, Sao Tome, and Principe, Gabon, Republic of Congo, Democratic Republic of Congo, Uganda, Kenya Somalia, and Indonesia.

It also Passes through Coral Atoll of Maldives and Kiribati (a country in the central Pacific Ocean.)

Saudi Arabia is a country in Western Asia. It is situated in the Northern Hemisphere. So, clearly Equator doesn't pass through it as it is situated to the north of Equator.

More Info: en.m.wikipedia.org