The present invention provides a nanoparticle and cell induction agent, capable of releasing a target substance in a weakly acidic pH environment. Specifically, the present invention provides a nanoparticle comprising a peptide and a particle-forming component, the particle-forming component forming a liposome or a micelle, the peptide having a sequence with 2 to 8 units starting with His (histidine) and ending with an acidic amino acid, wherein each of the units may be identical or different.
