Promoting generic drugs can reduce the financial burden on patients and improve healthcare finances. The insurers have been conducting promotional efforts, such as direct-mail campaigns, but little is known about the public’s perception of generic drugs and effective message strategies for promotion. In 2018, we conducted a web-based survey of middle-aged Japanese men and women that investigated: (i) their perceptions of generic drugs, (ii) the association between perceptions and willingness-to-pay for brand-name drugs relative to generic drugs, and (iii) potentially effective forms of information provision to alter individuals’ perceptions. Of the 1,005 respondents, over half perceived generic drugs as having the same level of efficacy and safety as brand-name drugs. While willingness-to-pay was dispersed among respondents, two factors were associated with small willingness-to-pay: (a) perceiving generic drugs as having the same level of efficacy and safety as brand-name drugs and (b) perceiving that promoting the use of generic drugs is important for controlling medical expenditures. Moreover, presenting potential savings over five years by choosing generic drugs was a potentially effective tool for altering perceptions, relative to showing monthly savings. Our findings suggest that certain parts of the population still have high willingness-to-pay for brand-name drugs, and strategic communication to alter perception could be effective in promoting the use of generic drugs among those who are price-inelastic.