Inside the caldera of the Hakone volcano, earthquake swarm (over 1, 800 events) and crustal deformation (ground inflation) were observed from January to February, 2013. The swarm activities were concentrated around the fumarolic area (Owakudani) and the central cones (Mts. Kamiyama and Komagatake). In order to reveal fine subsurface electrical structure, we carried out complementary audio-frequency magnetotelluric measurements at 15 sites in the end of April 2013. As the result of provisional remote-reference processing using local sites, we obtained fair magnetotelluric responses at most sites.