thumb|Sutthisan Winitchai Road in the area of Huai Khwangthumb|Ratchada-Sutthisan Intersection, where Sutthisan crosses Ratchadaphisek Roads on the boundary between Huai Khwang and Din DaengSutthisan Winitchai Road (Thai: ถนนสุทธิสารวินิจฉัย), commonly referred to as Sutthisan Road (ถนนสุทธิสาร) is a road in form of soi (side-street) in downtown Bangkok and is the name of the neighbourhood that the road runs through.
This road was built in 1956, its name "Sutthisan Winitchai" in honour of Phra Sutthisan Winitchai (Mali Bunnag), a former civil servant of Ministry of Justice, who the heir consecrated his private land to the authorities to cut the road for public utilities.
The road starts from the east side of Phahon Yothin Road, then it meets another short road that also branches from the east side of Phahon Yothin Road at the Saphan Khwai Intersection, Saliratthawiphak Road (ถนนสาลีรัฐวิภาค), then cut through Vibhavadi Rangsit Road at Suthisan Intersection in front of Sutthisan Fire and Rescue Station, and cut through Ratchadaphisek Road at Ratchada-Sutthisan Intersection as far as terminates at the bridge across the Khlong Lat Phrao canal by converges with Soi Lat Phrao 64 (Yaek 4 or Soi Ketnuti), a total distance of 4.51NaN1.
However, Sutthisan Road has another name, after 5001NaN1 of the road starting point, it will be a section called Inthamara Road (ถนนอินทามระ), which is named after Pol.Lt.Gen. To Inthamara, a former police who devoted his own land to develop streets and alleys into residences of police officers at that time. At present, the name Inthamara has become all 59 sois of Sutthisan Road. In 2017, there was a court decision ordering Bangkok Metropolitan Administration (BMA) to use the name Inthamara Road. Originally in 2004, it was all changed to Sutthisan. The BMA claims that the name Sutthisan is more widely known.[1]
Sutthisan is considered one of the old areas of Bangkok. Nowadays, it is considered a suitable area for living as it is a convenient location. Because it is a shortcut or a connection to the main highway, both Phahon Yothin and Vibhavadi Rangsit Roads. The arrival of Saphan Khwai Station of BTS Skytrain in 1999 and Sutthisan Station of MRT Blue Line in 2004 increased the area's high land value. Especially on Phahon Yothin or Saphan Khwai side, where many condominiums are located.[2]