Be careful. In this way, the device is working between two phases of a 3-phase a.c. source. Be sure the device's ground is OK and it does not link to any of those two leads.
Many single phase circuit share the ground and the single phase neutral.
For safety, it's better not use this approach, especially those who not has much knowledge about electricity.
If someone still want to try, an advice is to insert an additional switch to allow you disconnect your device from the ac source completely (both leads discnnected when you turn off the device).
For low power rating devices, a 110 to 220 convert adaptor is not very expensive and is safer.
For the devices >350W, such as hair dryer or cooker, find a similar product designed for 110V source is often a better choice.