Reserved Word of & in Oracle SQL Statement

Question

I used Oracle as my database, but I faced a problem when I execute the statement below INSERT INTO [TABLE1] ( AStringField ) VALUES ( 'THIS IS A & Ampersand' ) The error is something like this, the data is too long... But I check my field lenght is large enough to store the data ( The actual lenght is varchar(50) ), Basically it only happen when I insert A & symbol in my statement, if I remove the & symbol, the statement was executed successfully... Can anyone help me ??? Thank you