A novel recovery method is proposed for gold ions using poly(tyramine), which is reductive and has easily manipulated solubility. Tyramine, which has phenol and amino groups, was polymerized using horseradish peroxidase. When the HCl concentration in solution was increased, poly(tyramine) solubility decreased, probably due to chloride ion coordination with the poly(tyramine) amino group. Poly(tyramine) was highly soluble at pH <4.0 in the pH region. When the polymer was reacted with gold ion solution in HCl for 48 h, the maximum amount of gold ions obtained was 4.0 mol/kg in a two-step reduction isotherm curve. Filtered reduced gold particles with poly(tyramine) were immersed in 0.1 M HCl solution, resulting in dissolution of the poly(tyramine), and the gold particles were then easily recovered by filtration. Adjusting the pH of the filtered solution to 7.5 allowed recovery of the poly(tyramine) as a precipitate, which could then be reused to reduce further gold ions.