you have to go to lavender town its there
you go in rock tunnel then it will go in lavender <- this is not the right answer
go up the elevator.
go right of lavender town
Either go North from Lavender town or go East from Cerulean until you reach like the corner of the map. Then you have to surf in that water and go around until you reach it.
Lavender Town you need to go into the tent.
The top of Lavender Town's tower
Go through the rocky tunnel
You go though rock tunnel
Go to the Radio Tower in Lavender Town
Underground Tunnel, West of Lavender Town
Go to lavender town go to the right and there it is.