By
Bank Indonesia's consumer index was at 126.4 in December, up from 122.1 in November.
A reading above 100 indicates consumers are optimistic.
About 4,600 people from 18 cities were surveyed.
Residents, according to the survey, were expected to increase their spending on household consumption in the next three months.
Indonesia's annual inflation rate in December was 3.61 percent, the first increase since June.