The generation of an isolated attosecond pulse (IAP) has been pioneering new breakthroughs in the field of ultrafast science since the first measurement in 2001. Here, we review the recent technological advances in the IAP generation from the view point of ultrabroadband attosecond continua, which support sub-50-as pulse generation. We also introduce our studies for the IAP generation based on a high-intensity Ti:sapphire laser system. In particular, we report the generation of the attosecond supercontinuum spectrum with an extremely broad bandwidth of 70 eV at full width half maximum, which suggests the generation of 32-as pulse, based on the combination of the amplitude gating and the double optical gating schemes using the driving laser field with sub-two-cycle duration. Our approach will be a promising method for generating the shorter IAP that achieves an improved temporal resolution for investigating electron dynamics in unprecedented attosecond timescale.