| Country: | JPN |
| Type: | National |
| Route: | 178 |
| Map Custom: | yes |
| Length Km: | 201 |
| Length Round: | 0 |
| Length Ref: | [1] |
| Direction A: | West |
| Terminus A: | Prefectural Road 328 in Iwami, Tottori |
| Direction B: | East |
| Terminus B: | in Maizuru, Kyoto |
| Previous Type: | Route |
| Previous Route: | 177 |
| Next Type: | Route |
| Next Route: | 179 |
National Route 178 is a national highway of Japan connecting Maizuru, Kyoto and Iwami, Tottori in Japan, with a total length of 201 km (124.9 mi).