To provide a photobase generator generating a base by absorbing UV light of shorter wavelengths; and provide a pattern forming material excellent in resolution with good balance of characteristics between exposure part and non-exposure part, usable as negative/positive dual-purpose type resist.

This photobase generator expressed by formula (1) generates a base expressed by formula (2) by selectively absorbing UV light with 190-230 nm wavelengths. In formulae (1) and (2), R¹ and R² each independently is H, methyl, cyclohexyl or cyclohexyl substituted by 1-6C alkyl; when either R¹ or R² is H or methyl, the other is cyclohexyl or cyclohexyl substituted by 1-6C alkyl; R¹ and R² may bond together to form a ring.