ATHENS — The country’s new conservative prime minister, declaring that Greece was “no longer the black sheep of Europe,” on Saturday announced a series of corporate and individual tax cuts, along with a plan to encourage investment.

Prime Minister Kyriakos Mitsotakis outlined the measures, intended to bolster a country dogged by years of austerity and the vestiges of a decade-long financial crisis, at a trade fair in the northern port of Thessaloniki as thousands protested outside to demand greater rights for workers.

Mr. Mitsotakis replaced his leftist predecessor, Alexis Tsipras, in July with promises to give the slowly recovering economy a lift by attracting foreign investors with pro-business policies that his New Democracy party has long promoted.

The cuts, which included taxes on corporations, dividends and people in the lowest income tax bracket, were detailed before an audience of Greece’s political and business elite.